There's also the thing that a gay man is never going to threaten their relationship with their girlfriend. Like every hetrosexual man out there, they may find their girlfriend sexay, and who knows said girlfriend may decide to leave them and vanish off with said threat. Afterall, men find lesbians hot and they only need a good man to show them what's what, so maybe girls feel the same way about gay men?

But gay guys, well they can talk handbags with their girlfriend, but there's no danger that the girl may vanish off with the gay boy.

It's sad if someone feels that controlling / insecure about their relationship - or indeed so badly misled about such things, but some people are.