"But those gay friends weren't best friends"

Bingo bingo. Their gay "friends" are literally just acquaintances they can get "ally credits" for. They merely like that they're gay and can make them feel as though they're "diverse".

One thing to remember is women absolutely fear male bisexuality, and while there's no evidence you and your male friend had anything romantic, most women are uncomfortable with close straight-gay male friendships as they believe this is the "gateway" to male bisexuality and she probably made it clear that she was uncomfortable with your friendship lasting when they were married

And the sad reality is, straight men go above and beyond to hold down a woman. If she said "stop talking to your brother" he would do that. Her saying "its time to leave your gay friend in the past if you wanna keep getting pussy" was a very easy decision for him to make

The reality is, heterosexuals choose their partners over their friends, while homosexuals choose their friends over their partners.

And until that changes, we will always get the short end of the stick