First post on the BSN and it's talking about my favourite subject!
Sorry guys, I just had to jump in here when talk of same-sex relations in Tevinter society came up. I'm actually a historian who specializes in male same-sex relations throughout history, and have a keen interest in Classical sexuality as my degrees would attest to. If we're going off the assumption that Tevinter is based off of the Roman Empire then I think we can get a pretty good idea of how same-sex relations are handled in Tevinter, based on that assumption as well as what Brother Genitivi wrote. There seems to be a misconception with people that same-sex relations between men in ancient Greece and Rome were a-okay and everyone was doing it and there were no rules when, in fact, there were a lot of rules, both legally as well as socially.
In Rome, sex between two men was a tricky situation to navigate. Before Emperor Augustus took over and turned the Republic into an Empire, there was something called 'Stuprum' which in Latin translates to 'defile' or 'disgrace' or 'violate'. This law is kind of an issue because we don't know how it came into effect and where it came into effect, but it seems that it was usually used in cases of sexual assault and rape. Stuprum was a concept that covered a variety of sexual habits, from adultery to the notion of free men and slaves and the hierarchy of sex. However, stuprum lay mostly in moral ideologies rather than official legal codes. After Augustus came in to power, he made actual laws concerning sexuality and sexual norms, such as lex Julia de Adulteriis Coercendis among others. However, these laws did not touch male same-sex relations, and for the most part, during Roman times, there were no laws, per-say, that regulated male same-sex relations.
However, as stated above, there were social norms and social 'rules' that regulated male same-sex relations. Penetrative sex between a freeborn man and his slave was alright-- there was nothing bizarre about that and was not shamed in any manner. After all, a slave is property and a man can do what he wishes with his property. Sex with male prostitutes was also not frowned upon. Again, they were there to service a person. However, when we come to same-sex relations between two freeborn men, that is when things get tricky. It wasn't as if it was illegal, but it was certainly frowned upon, especially if it was between two adult men. The Romans differed from the Greeks when it came to same-sex relations because they didn't believe in the practice of pederasty, where an eromenos (a young man about the age of 13 to 18) carried on an emotional and physical relationship with an erastes (18 to 30 years of age). The Athenians in particular felt that the relationship between an eromenos and an erastes built strong male citizens as they were taught about the world as far as politics, warfare, philosophy, and sex went. However, once the erastes was old enough he was to marry and produce children, while the eromenos would become an erastes himself and teach the newer generation. The eromenos and erastes could remain friends, but their physical relationship was supposed to end there.
The Romans did not practice this, and found the custom of same-sex relations between two freeborn men to be... distasteful. It wasn't illegal, but it also wasn't praised nor talked about in a very positive light. It was joked about and there was definitely some judgement. Especially if it contained penetrative sex. If you penetrated a man it was seen as putting that man in the role of a woman, and that was a big no-no. Masculinity and the male ideal played an important part in the influence a Roman male citizen could have in both the Republic and the Empire. How much power a man had was directly linked to how those around him perceived his masculinity—or lack thereof. His sex life and personal habits were always under the scrutiny of his peers. Of course some men went off the beat and path, most famously Emperor Trajan, who was married but never had any children and spent all his off-time with slave boys (when he wasn't busy expanding the empire), and Emperor Hadrian, who had a rather famous relationship with a freeborn Greek man by the name of Antinous.
So if we're going to use the basic Roman model on Tevinter, it seems like it is frowned upon and that there are certain duties a man in Tevinter is supposed to carry out, such as child rearing in order to continue the bloodline. But that there are no strict rules, per-say, against same-sex relations between men. It's just heavily frowned upon and scrutinized. If Dorian is gay, I think it would make for an interesting storyline, as he would push against these social norms and expectations. It'd also make him a bit of a black sheep (more than he already is).
TL;DR: Romans thought sex between slaves was okay but sex between freeborn men was heavily scrutinized.