You don't sound like a homophobe per se just from reading your post, but you are more than just a bit narrowminded. Why can't you shower with a gay person, are you afraid it's contagious or something? Btw, chances are you've showered with lots of gays already, you just didn't know it. Is that what you want, for gays to hide who they are, just for your benefit? Lemme tell you something... That's not a workable way for a free nation to function.
Most assuredly, you're not most gay men's type, and you're not going to lose your mojo from having to shower nekkid around them. Relax, okay? Gays are merely regular human beings, just like you.