I've actually just written a little about this in answering another question, and I'll copy in what I wrote there, with some added detail. For women in much of the Victorian period, it would have been tolerated to live together, swear love to each other, even exchange rings and call themselves "married."

I will give you all a moment to find the monocles you no doubt just had pop out, and I'll begin.

As Sharon Marcus shows in her book Between Women: Friendship, Desire, and Marriage in Victorian England (2007), the intense expression of love and affection between women was encouraged by society, and women were invited to enjoy looking at the bodies of other women, even in sadistic/masochistic acts--adult women whipping younger girls was a popular topic in pornographic books for women. Reviewers of books that describe female-female desire often made horrified protests against characters they saw as "monstrous" and overcome by horrific sexual desire, but despite such printed protestations the lived reality was very different, and women living in long-term relationships with each other were often accepted and acknowledged by society. Marcus suggests what was shocking to Victorians was not the female-female physical desire in itself but the idea of sexual desire outside of a stable relationship; excessive love of sex was considered deviant and dangerous, and the female desire for women outside a monogamous relationship was thought to be a result of sexual desires overflowing their proper channels.

Marcus describes women who exchanged rings and called themselves married. As Marcus writes, "Women who established longterm relationships with other women, by contrast, saw themselves, and were seen by others, as placid embodiments of the middle-class ideal of marriage: a bond defined by sex that also had the power to sanctify sex" (21). Friendship, love, and even physical desire were expressed freely in letters, and hand-holding and kissing were not considered shocking, but the norm for female friends. For two women to sleep in the same bed, even touching and kissing, was not in itself considered problematic, and was even encouraged. In short, "Sexual relationships of all stripes were most acceptable when their sexual nature was least visible as such but was instead manifested in terms of marital acts such as cohabitation, fidelity, financial solidarity, and adherence to middle-class norms of respectability" (49). Out of propriety, such pairs would have been referred to by others as "friends," which can make it tricky for historians to separate romantic relationships from close friendships.

Marcus uses the example of Rosa Bonheur and Nathalie Micas, who are written about as having a "higher levels of involvement and intimacy than even the closest of female friends" (50). They lived together, shared their finances, designated each other as their heirs, and arranged to be buried together. Friends referred to the couple's "deep affection" and "long companionship", even calling them a "couple." Bonheur even referred to Micas's mother as her "mother-in-law" (51). Marcus uses as another example Frances Power Cobbe and Mary Lloyd, who were acknowledged as "a conjugal unit who lived and traveled together and were to be jointly saluted in correspondence" (51), and Cobbe even referred to Lloyd as "my old woman," "husband," and "my wife" (52, emphasis in original). Others writing about and to them referred to them in the plural, and referred to "their" house, garden, etc.

In another example, this time from the United States, the obituary of Annie Hindle from 1892 writes that she was married to Annie Ryan "by a minister of the gospel, Rev. E.H. Brooks" in 1886. Annie Hindle was known as a "male impersonator" and would often wear "men's" clothing and adopt a masculine name, but the obituary points out that "That they could live together openly as man and wife, the husband always in female attire, and yet cause no scandal, is the best proof of the esteem in which those around them held them" (Marcus 200). That the article comments on the possibility of a scandal shows the shifting attitudes about this at the end of the century, and I will address more of this later.

It should be noted that the stigma you mention attached to certain sexual roles would not have been applied, as discussion of the sexual roles of others in this period would have been very taboo and very strongly censured.

Other letters and memoirs write of attraction, infatuation, and intimate encounters, although they usually express these much later and in a veiled way. The use of euphemisms is key, and it's interesting to me that Victorian propriety not only swept details under the rug but made it possible to express those very things in a socially acceptable way, even to the point of relationships being acknowledged and accepted by society. Marcus alludes to the fact that, given the Victorian stereotype of lesbians as "mannish" and degenerate, supposdely exhibiting such physically signs as unnaturally large clitorises, the fact that women did not appear this way "allowed them to go beyond the limits assigned to their gender without being perceived as mannish or unladylike" (56).

In her article "The Trials of Alice Mitchell: Sensationalism, Sexology, and the Lesbian Subject in Turn-of-the-Century America", Lisa Duggan makes the argument that the concept of lesbianism first really took shape at the turn-of-the-century, and that the public emergence of the idea of "the lesbian" in the 1890s turned female-female relationships into a potential source of shock and condemnation, such as the trial of Alice Mitchell for insanity in the United States after killing her lover. Mitchell's trial characterized her as demonic and dangerous, with a pathology for violence linked with her transgressive desire. Thus, once a figure was created in the public imagination, the euphemisms and taboos that made female-female relationships possible faded. Duggan writes that the broader use of the "mannish lesbian" image was itself double-edged: it was used to condemn lesbians as deviant and unnatural, and also by lesbians themselves as a subversize self-identification to form an identity.

It must be mentioned that the above Victorian acceptance of female-female intimate relationships generally applied to upper-class and middle-class women, but it did not hold true for the working class. Marcus writes that, "A few working-class women wrote about intimate friends in their lifewriting, but most avoided overt displays of affect and mentioned female friendships only briefly, focusing instead on relationships with female employers and coworkers that did not lend themselves to unreserved expressions of feeling" (69). The working class simply didn't have the distance from others that would have created the space in which an intimate relationship could emerge.

Male-male relationships could also be tolerated and even acknowledged if they were very discreet, but to a lesser degree and with more social censure, as well as including the stigma you suggested for the passive partner.

It would also be interesting to know how the Sacred Band of Thebes and other armies of homosexual pairs were perceived. Were the soldiers' relationships generally accepted, or even perceived as something common and normal? How did other peoples react to these soldiers' sexualities?

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(By the way, this might be an example for "egalitarian" homosexual relationships in ancient Greece.)

Yes. The precolonial Philippines certainly did (and really, more than tolerated). In fact, the role of what we would call probably LGBT people in the modern West was rather prominent in the society. Many were in leadership roles, along with women (women were even more prominent in leadership). For example, a religious leader was, in general, supposed to be a woman. If the person wanting to be a leader was not a woman, then they would need to take up the social role of “being a woman”, that is, taking up the dress and social behaviors of women. Sex and sexuality was generally pretty egalitarian in the Philippines prior to Western influence. I have written in this sub previously on these topics, so I will link one of those below:

https://www.reddit.com/r/AskHistorians/comments/90euz4/comment/e2qa6bp?st=JQSFBUYJ&sh=e4816598

Something I will add, and which is discussed in the source I cite in the link (the source in part reviews sources on Philippine sexuality), is that just because relations between various genders were pretty egalitarian, it does not mean that there were not gender expectations. “Performing gender” was in fact a huge part of the society, as discussion on religion shows. Part of performing gender would include sexual behavior, as gender and sexuality were/are linked in the conceptualizations in “classical” Philippine cultures. There were expectations of who religious leaders were, for example. However, perceived gender and sexuality differences were not generally used as a tool of oppression, which I think is what your question seems to be about.

This answer from /u/cthulhushrugged could interest you.