I'm confused as to why my gay ex always hung out with girls.

I'm gay so that means I like guys right? So I hang out with guys in my class since we have more in common. My ex always hung out with girls and partied and whatnot. One time he went on a Paris trip and he was the only guy that went. He's slightly feminine but I never understood why some gay people choose to hang out with girls all the time? Help me understand ._.