I just need help understanding when he seemed so straight before?

My exhusband and I got married young and like many, we had a very active sex life in the beginning. Even independently of this, he always seemed very, very attracted to women.

We were both early twenties and you know how younger men will sometimes have a wandering eye to attractive women in public. I would notice this when we were younger and he never had wandering eyes for men, but I saw him notice attractive women from time to time. There were also a few times I could tell he had a little crush on another woman in our lives, like a cute barista at our local coffee shop or something. He was never inappropriate or cheating, and that's not the focus on my post.

Additionally, maybe this is weird, but I was pretty aware of what kind of porn he watched and it was heterosexual and female focused. There were a few times I borrowed his phone and he had incognito tabs in the background and (I know it's bad) but I peaked out of curiosity and it was straight porn. Very heteronormative types of porn too.

A few years ago, he did share with me that he occasionally watched male-male porn with effeminate men, because one time we were sharing stuff with each other to sort of reconnect our sexualities.

Anyway, today we are still friends and we are divorced. He presents a lot more effeminately now in his style and identifies as gay.

I'm just confused because he seemed so into women before. Can people's sexualities completely change? Can someone just really lead a straight life like that? I guess I just always imagined confused/closeted guys going through the motions in their lives, but then being like, "I guess deep down I always knew I was gay though, because I never was drawn to women in porn, and I never checked out women." Stuff like that. But he did do those things. So I'm really confused!