Are you sure? 
Straight guy checking in, who’s probably gone to more gay clubs than straight clubs. Reason? I tend to go with female friends, and they tend to like gay clubs because they’re LESS of a meat-market than straight clubs. I go to clubs to dance, not to get easy sex, so I’m fine the less-meat-market feel.
I’ve gotten hit on a couple times, but never very badly, and never as badly as I’ve been hit on by a guy at a straight club (I have long hair and am easily mistaken for a woman in dimlighting; this guy started freakin’ all over me, and it was only not disgusting because I was laughing so hard at the mistake he was making). The most attitude I’ve ever gotten at a gay club has been the door guy asking curtly, “You know this is a gay club, right?” When we said yes, he took our money and let us in.
It’s not the least bit something to stress over, in my experience.
Daniel
I am a hetero guy who use to frequent gay clubs (too much work these days). I went to regular clubs to meet women, I went to gay clubs to dance. It is great because you absolutely do not give a damn what anyone else thinks of your dancing as you have no intention of trying to get together with them. Lots of fun. It is also a great ego boost to be hit on by anyone, male or female.
I sort of feel like I know what it’s like to be a straight girl getting hit on by guys due to gay bar experiences. Every time I goto a gay bar I get mauled by guys. Not that I’m complaining, it’s very flattering, and hey, guys are guys.
Turning guys down when getting hit on was sort of a challenge for a while; “sorry, I’m straight” sometimes seemed to garner a little bit of resentment. I think some people sort of feel like you’re “slumming” coming to their bar or feel as though you’ve led them on somehow. I eventually came to just use “sorry, I’m here with somebody.” Universally honored, and no hurt feelings.
As of about 10 years ago, this concept had come full circle in New Orleans. The two largest gay dance clubs on Bourbon Street became straight pickup joints, because it was common knowledge that loads of straight women hung out at those clubs.
In New Orleans, there’s a good deal of overlap between the gay and straight club scenes. However, Priam’s advice would still hold – try to get a feel for a place before hanging out there. Ask your club-hopping friends for info.
“Wait a second, this lesbian bar doesn’t have a fire escape! Enjoy your deathtrap, ladies!”
For some reason I’m reminded of the Simpsons episode where Homer and Bart tour the steel factory that suddently becomes a gay bar after closing.
No, no…please do. 
And winterhawk, try to get your spouse to relax a little. It’s SO obvious when they do the “I’mstraightI’mstraightI’mstraight” SO-stranglehold all night… 