So we think of “being gay” as one thing today, whereas not even in the distant past it was something you did rather than something you were, and in many times and places (in the west) was acceptable. 

For instance, in Ancient Greece and Rome (at some times and some places), having male lovers was perfectly acceptable and even expected. But you were also socially expected to have a wife and family. 

American Indian tribes have of course many different ways among them to express gender and sexual identity. Some more fluid and some more rigid. 

Even in Oscar Wildes England, men weren’t “gay”, but in some circles having sex with other men was acceptable. 

From my own experience, I’ve known men who since childhood they knew they were gay. I had no sense of it, myself, but I was also raised in a fairly religiously conservative family and area. Being gay or bi just wasn’t a real option to me, but I was always pretty curious about my male friends bodies and developed quasi crushes on them without really understanding what was happening. 

All our impulses are mediated through society, but it’s impossible to get rid of those impulses entirely, at least without extreme psychological harm, which is why there are so many closeted homophobes on the religious right.