I think my boyfriend is gay..

Greetings from the United Kingdom. I'm 18 and my boyfriend is 17. We live in a flat with our fur baby, Patty. I love my boyfriend a lot but I am very convinced that he may be into men. Last year before having sex for the first time, we asked each other about our kinks and things we enjoy. He told me he thinks he's into anal play. I asked him if he was gay then and he said no but he told me he had sex with a boy before because he thought he was bisexual. He told me that although he enjoyed the feeling, he felt awkward because he felt no physical attraction to the boy so that determined he was straight. Recently he asked me if I would ever try pegging and I told him I'd think about it. Now I am questioning his sexuality? Is my boyfriend gay?!