It's not like they all sit around between matches and go at it. It's probably a big deal for there to be a gay wrestler in the ranks at the WWE.
Many men do alot of things for humor and not for emotion...like poke fun at gay guys or do things that are sexually "suspect" but it's all in pure fun to them because they assume that most of the guys around them are just as straight as they are. They don't consider someone ever being offended or feeling ostricized from the behaviour.
Really, it's considered a sort of betrayal to find out that the dude you've been teabagging and dick slapping could have possibly liked it...it's the case in alot of sports fields. Mostly because those who don't understand homosexuality think it's some sort of communicable disease that if in the wrong company, can turn into a major outbreak. It's weird.
...but to answer your question again, I don't believe that there's a great deal of gay sex going on behind the scenes of the WWE. Even if there was a hook up or two, it'd most likely be outside of an arena or on some downtime.