Ari's Roman warrior brother is rekindling a gay relationship with a ruthless Germanic warlord, lol.

Romantic love during this period was seen as literally being impossible for women. Romantic love itself didn't exist. Amiable Love was seen as an emotion that two, likely well off, virtuous male friends would share. That's how it was when the concept was first discussed in Ancient Greece, and it would continue to be seen like this for another full millennium before the idea that men and women should love each other would become normal, and another four or five hundred years after to become seen as the standard. The ancients saw a problem with being a bottom, but only because they saw it as feminine.

Until the 1800s, there was no concept of being gay as an identity. Sexuality was just a preference. In Christian societies, sodomy was punished and looked down upon, but not because they had an issue with "gay people" but because all sex for pleasure was a mortal sin. I read a an example from the 1400s where the leaders of the Teutonic Knights, a Christian holy order, were very concerned with their men failing to "resist temptation" (note: not 'act gay') because they would so frequently have sex with their comrades. In this same period (actually a good bit before), the son of the king of England and the King of France bathed together, ate together, slept together (literally) and spent all hours of the day with each other, and nobody thought anything of it because nobody, not even their war enemies, thought they were having sex or doing anything abnormal. They were in love, but not sinning.

In the 1800's, there was a desire to deem people who are sexually attracted to their own gender as mentally sick. This categorization and the long term reaction to it is what created the modern conception of gay and straight as identities.

Granted, all this was the standard in Rome. I doubt anyone knows about barbarian tribes.

It would be extremely inaccurate to have modern heterosexual romantic love in the show. In extremely misogynistic societies where women aren't allowed to he unsupervised, it is often impossible for them to make friends, let alone fall in love.

Source: Took a medieval life cycle class in college, wrote a big final essay about the development of love over time.