This is a tricky question to answer, because while society was never as squeamish as moderns imagine, people simply didn't explicitly, rigorously document their own sex lives (apart from certain notable examples like Anne Lister). In particular, we always have a hard time finding out about the private lives of women and the working classes.

The most effective method was probably coitus interruptus and regular breastfeeding and as we know, compared to modern contraceptives, those have a low success rate at preventing pregnancy.

Prior to the advent of reliable, accessible modern birth control, men and women were acutely aware that sexual intercourse was very likely to lead to pregnancy. The most effective method at the time was simply to not have sex at all or infrequently (perhaps once a week) - abstinence - and despite the jokes about teaching that as birth control today, there is evidence that changes in at least English fertility rates were affected by deliberate attempts to limit family size. That is, abstinence on the part of women: men, particularly in urban areas, would have found it quite easy to meet sex workers, whom they paid to take on the responsibility of a possible pregnancy. Unfortunately, it's impossible to tell how many couples agreed to abstinence together and how many involved a husband stepping out on his wife, but there is a great decline in fertility over the nineteenth century and early twentieth that simply can't be explained with the contraceptives available at the time.

We do see a number of wives in the nineteenth century that have several pregnancies close together at the beginning of their marriage, then a few more spaced apart, and then no more, often well before menopause would have forced the issue. In The Long Sexual Revolution: English Women, Sex, and Contraception 1800-1975, Hera Cook quotes parson Charles Kingsley in an 1849 letter to his wife: "I long to be back in your arms [all you my] cruel cold darling beauty [wish for is] to sleep by my side." His wife, Fanny, had had one child in 1844, then a miscarriage in 1845, a second child in 1847, a third child in 1852, a miscarriage in 1853, and their last child in 1858, fitting into the pattern - it seems highly likely that she deliberately chose to turn down sex in order to prevent the later pregnancies from occurring as quickly as the first three. Other wives weren't so lucky, and had to resort to subterfuge to avoid their husbands' attempts to enforce their conjugal rights (which, in a time when it was understood that the marriage vows were effectively a blanket consent to sexual activity after the wedding, were seriously understood as rights): some women had to make excuses for avoiding their husbands instead, staying up late with housework or claiming that a child needed them to sleep in the other bedroom.

So, paradoxically, the explanation of what married sex life was like ... is that it often wasn't really a sex life at all! Cook notes that oral and anal sex was highly stigmatized in the eighteenth and nineteenth centuries, and so broadly suggests that abstinence really meant abstinence (or fairly infrequent sex), not alternatives to procreative sex, though by the 1930s there seems to have been a relatively large fraction of married couples that resorted to anal sex despite neither partner preferring it, as a form of birth control.

These are excellent questions and the history of contraceptives needs a lot more work. I'm a classicist by training, so my knowledge of modern practices and anything outside Europe is quite limited, but I can give this a shot while we wait for someone with a better answer.

Since this question really focusses on behaviour, I think it's important to note that women have not always had a large degree of autonomy over their own sexual lives. Marital rape wasn't even legally recognized in Canada, my home country, until 1983. This topic is incredibly complicated, as the way people conceptualize marriage and marital harmony and sex change so much over time and between individuals. Generally, though, it is important to recognize that post-coital methods of contraception have historically been one of the only ways that women could have control over their own reproduction, and that abstaining or changing the method of intercourse has not always been an option.

I also really cannot answer the question on the frequency of sex, as that is something that is unique to every couple, even in modern times. I can say: frequent enough to propagate the species such that we survive today and have evidence that they attempted to prevent pregnancy so there were not more of us.

The ancient Greeks and Romans were very aware of contraceptives and abortifacients and had a number of recipes they used. Silphium was a commonly known contraceptive, but as it's now extinct we unfortunately will never know its active ingredients or effectiveness. Its presence in texts even outside of medicine and the fact that it was used to extinction may suggest it was effective, though. There are a few gynaecological texts from the Classical period we know about which provide more information on the subject: the Hippocratic Diseases of Women and Soranus' Gynaecia both include recipes for inducing menses, and both Galen and Dioscorides include contraceptive and abortifacient recipes in their pharmaceutical works. Despite the Hippocratic oath's prohibition of abortion, Diseases of Women includes multiple recipes to "draw out the menses" or "clean" [the womb], including suppositories of cucumber juice and sheep's fat; or of narcissus, cumin, myrrh, frankincense, wormwood, and galingale, pennyroyal, birthwort, and some 20 other recipes for ways a woman can ensure she gets her period (Diseases of Women 1.84-8). As these undoubtably were not incredibly effective (although this is up for debate- there is still much scholarly work to be done on the ways that suppositories could work to change the pH of the vagina, create a spermicidal environment, or effectively work as a diaphragm to block the cervix if inserted before sex), there were also surgical methods of inducing an abortion, however Soranus advices against these because they brought such an increased risk of perforation, bleeding, and infection.

Clearly these approaches are more for preventing a pregnancy after intercourse has occurred, rather than changing the behaviour before or during intercourse. I'm not aware of any classical text suggesting a husband abstain from sex with his wife to avoid pregnancy, however "coitus interruptus" was known and - presumably - used. I think it's also important to note that a Greek or Roman husband may have multiple women in addition to his wife where he "sowed his seeds" and so the burden of his progeny wouldn't all have been foisted onto one woman. The idea of sex correlating to marital harmony isn't very prevalent, though- marriage was a way to get legitimate children and continue your family line, you had girlfriends for sex for fun.

Jumping ahead a bit, the Medieval period sees a few new gynaecological texts. Notably coming out of 12th century Salerno was the so-called Trotula texts, one book of which seems to have been written by a female physician. The Trotula includes hundreds of recipes, many of which are intended to prevent pregnancy, seeing again many of the ingredients the Greeks and Romans used: pennyroyal, galingale, myrrh, cloves, etc. By this point, there are only references to bringing on the menses, with little to no reference to abortion - the idea that a pregnant woman would have used them to induce an abortion is avoided at all costs, and instead texts focus more on the restorative effect rather than the fact that bringing on menstruation is also a way to ensure that pregnancy does not develop. Clearly, though, the information was still circulating and women almost certainly were still using these methods for family planning.

This mindset continues into the early modern period- Louis Bourgeois, famously the midwife to Marie de Medici, wife of King Henry IV of France, was a prolific writer and, after millennia of the Greek physicians' theories of wandering uteri pervading medical literature, provides a very welcome practical voice to the annals of gynaecology. Nevertheless, she calls anyone who offers abortions remedies evil (Diverse Observations 2.205) and instead her work focusses largely on aids to pregnancy and birth, rather than contraception. This largely reflects the religious leanings of the church, whose teachings dictate that sex is intended for procreation and anything that prevents that (coitus interruptus, sodomy - either oral or anal sex, herbal remedies, hormonal birth control, etc) is at best immoral and at worst illegal. Consequently, during the medieval and up to the modern periods, it is unlikely to assume that a married couple would have commonly engaged in other forms of sex, but likely instead either abstained, accepted the risk of pregnancy or attempted to prevent it afterwards, or the husband had extramarital partners for his "needs." We do have some (very, very spurious) evidence of Roman wives engaging in different forms of sex, but it's not for contraception, and it's for comedic purposes rather than reflecting reality: Martial writes in Epigram 11.104 that he wants his wife to kiss him passionately, give him a hand job, and have anal sex with him, juxtaposing this with the claim that he is not a proper Roman man (who would not expect these things of his proper Roman wife!)

This brings us about to where my study ends. There's plenty of evidence from the Victorian period all the way to the 20th century of products intended to "induce" or "regulate" menses - likely with similar efficacy of our classical and medieval recipes (that is to say, likely not very), as well as the condom, made famous in the 18th century by Casanova, and the diaphragm in the 19th century. I can't comment on whether these products would have been commonly used by a married couple for contraceptive purposes, and I welcome more contributions by people who can provide context here.

Regarding breasts: they certainly were viewed as sexually appealing. Throughout history, women who could afford it often hired a wet nurse to preserve their figure and increase their fecundity, however this isn't precisely my area of study and it really deserves its own thorough attention.

For more reading, I recommend any of the original sources I mentioned here, and also:

Green, Monica. Making Women's Medicine Masculine: The Rise of Male Authority in Pre-Modern Gynaecology. Oxford: Oxford University Press, 2008.

---. Absolutely anything by Monica Green

King, Helen. Hippocrates' Woman: Reading the Female Body in Ancient Greece. New York: Routledge, 1998.

---. Midwifery, Obstetrics, and the Rise of Gynaecology: The Uses of a Sixteenth Century Compendium. Burlington: Ashgate, 2007.

Riddle, John M. Contraception and Abortion from the Ancient World to the Renaissance. Cambridge: Harvard University Press, 1992.

---. Goddesses, Elixirs, and Witches: Plants and Sexuality Throughout Human History. New York: Palgrave MacMillan, 2010.

This is a great question and a chance to plug one of my favourite books, Sex Before the Sexual Revolution by Simon Szreter and Kate Fisher.

The context of the book is that Szreter, as a demographic historian, noticed that there was an exceptionally broad fertility range in late 19th/early 20th century Britain, even with social classes and geographies. Essentially this implies that couples had a relatively sophisticated suite of methods to control pregnancy.

With Kate Fisher, they carried out a detailed survey of residents of old people’s homes in the North of England, revealing a lot about sexual habits in the 1920s.

The main findings were that contraception was achieved through a mix of methods. Predominantly these were satisfactory sexual relationships, so although abstinence within marriage was effective and often used, it was used temporarily, particularly after child birth, to space out pregnancies.

More popular was pulling out, which although not overwhelmingly reliable was still relatively effective. This did allow for a greater degree of sexual activity, but was still unpopular with men.

The final common method was the rhythm method, another imperfect-yet-effective technique. This was boosted by strong support from the Catholic Church (although, to nobody’s surprise, the male-dominated Catholic scientific establishment initially miscalculated and encouraged sex during peak fertility, leading to the method becoming known as ‘Vatican roulette’).

In general, a balance of all three was quite effective in limiting fertility. In general fertility control was seen as more of a woman’s responsibility, but men were not completely excluded from the discussion. It is notable that abortion was less popular, but by no means unknown, as a form of birth control, and women often reported at least knowing the identity of someone in their community who would provide abortions.

Beyond fertility, sexual pleasure was also quite important. While we often imagine this period to be quite backwards, many women reported high levels of satisfaction with their partners. Sex before marriage was also not uncommon, although usually with just one partner - it was still reserved for serious relationships. Women were still expected to be virgins at marriage, so definitely couldn’t talk about past experiences with their husbands (sometimes a problem if trying to express sexual preferences).

Sexual knowledge was generally passed between men in male-dominated spaces such as the factory or the pub, whereas fewer female spaces existed. Men often reported receiving sex education from colleagues.

Ultimately the answer to your question is that there was a huge variety of sexual experience in this period. Some couples reported high levels of satisfaction, others did not. Dissatisfaction could result from an overly-persistent husband, a lack of attentiveness in bed or embarrassment and shame around the act itself. Fertility control was relatively advanced, but very imperfect. Sexual knowledge was exchanged, but predominantly among men. In short, sex was as popular as ever, but the variation in quality was perhaps higher!