One of my GFs from college converted and we hooked up. Had some fun with other girls at that time, but she definitely WAS crazy. I broke it off after a while. Great fun when she was sane, but I couldn't bear it when she wasn't.
Wouldn't trade the experience for the world tho! Enjoy! Have a good time, but don't be afraid to bail if it gets bad.
She ended up marrying her next GF who was also smokin' hot. I'm still good friends with them. It was hilarious that her gf and I would swap war stories about her!
Edit: I can't believe how many prudes are here! If you have the chance to do something like this, DON'T HESITATE! Don't worry about finding a wife. If you're able to hook something like this up, you probably aren't going to have a problem finding "wife" material elsewhere. This is a moment that I GUARANTEE that you'll treasure for the rest of your life!