Welcome to the group. It was the opposite with me. I started out gay, & over the years became bi-curious.
It happened long ago when I discovered so many gay males can't seem to pair off into a relationship without having sex with others outside the relationship & cheating. Many of the gay singles were outright whores, going through many sex partners in a very short period of time, & it was often with people they hardly knew.
This was at a time during the AIDS epidemic, when so many were suffering or dead from the disease, but so many gays seemed totally oblivious about it, like they simply didn't think they'd catch it, didn't seem to care, or decided to just totally ignore the threat... especially in gay bars after a couple of drinks.
Many of the ones that survived that era, caught other diseases, or were lucky enough to have caught it late during the epidemic when very expensive treatments were developed that helped people with AIDS survive for decades instead of months or a couple years. But make no mistake about it, the disease or complications related to it still do eventually kill them.
This carelessness, & frequent multiple sex partners among most gay males was a mega turn-off for me even before AIDS, with the threat of a painful, & fatal disease on top of that... which everybody seemed to be carelessly catching, I walked away from it all. I decided to abandon gay life.
Over the years of no male partners anymore, I found myself mildly attracted to some women occasionally.