He claims to be bisexual because he thought he was gay for many years. Having been raised by lesbians, without a father as a role model, he was effeminate. After high school he was set upon by gays, who told him he set off their gaydar. So he became gay. He lived that lifestyle. Until some time during college. He invited a young woman home with him, I think to work on a project. They got drunk, had sex and he finally realized that this is how it should be. He is now married to her, they have a daughter together. And he says you couldn’t pay him to go back to the gay lifestyle.
So, he’s pretty much saying in other words, that he “used to be” homosexual.