First of all, please allow me the honor of introducing you to the Medieval Penitential Sex Chart compiled by canon law scholar James Brundage for his magisterial Law, Sex, and Christian Society in Medieval Europe.

Basically, Brundage went through the body of surviving early medieval penitentials, or handbooks listing various sins and their penances, to delineate when married couples were allowed to have sex according to those books. Of course, we don't know whether or how the penitentials were actually used. Some of the penances are severe enough to suggest they weren't intended to be literal. And the question of just how far into the laity the Church's legal and educational reach extended in the early Middle Ages is...highly debated, to say the least.

It's really not until the twelfth century that the Church works to codify and streamline its body of canon law, which governs sex and marriage in addition to, you know, the actual Church. At that point, though, the background assumptions of the penitentials are made clear. Sexual desire is a normal part of being human in a post-Fall world, and must be expressed only in the context of a matrimonial union. Husbands and wives actually owe each other sex upon request (provided it's not on Sunday, in a church, etc): this is called the 'marriage debt.' (So obviously we can rule out a medieval notion of consent or spousal rape).

That is, of course, just from the perspective of the Church and the clerics responsible for enforcing the rules (on which point, though, note that the 11th-12th century also brought renewed high-level vigor for clerical celibacy, but clergy from parish priests on up the scale continued to live with de facto wives until, well, until the Reformation allowed it for real, if you were Protestant). Actual cases brought before canon law courts of men and women trying to argue that they were or weren't married make it pretty clear that medieval people looked for sex both inside and outside of wedlock like, well, like people do.