Since I don't qualify, I'm answering for my bf who married his wife in his late 20s having never had sex with a man and claiming he had no idea he was gay. For reasons particular to him (not the least of which is that he had also only had sex with one woman, twice, prior to his wife despite being a very good looking, popular guy) I find it difficult to believe he wasn't in a lot of sexual denial.
However, he believes he didn't know he was gay until 10 years later and would have stayed married to his wife if she hadn't disliked sex so much, which he had come to like a lot. Once it was clear they were incompatible, however, and he was ready to move on, it wasn't women he realized he wanted to move on to. And the rest is history.