Adorable girlfriend gets fucked by horny friend for money in group sex

I'm not sure what to make of this situation. My girlfriend is a total babe, and she's been looking for some extra cash lately. She's been offering up her services to anyone who's willing to pay for it, and it seems like she's been getting plenty of offers. I don't really like the idea of her sleeping with other guys, but I can't blame her for trying to make some money. Anyway, I've been keeping an eye on things, and it looks like she's been getting pretty wild lately. Last night, she called me up and told me that she had hooked up with a guy who was willing to pay her for sex. She said that he was a big fan of group sex and that he was looking for another guy to join in. I wasn't really interested, but I figured I might as well go over there and at least have a drink with them. As it turned out, the guy was actually pretty cool, and my girlfriend seemed to be enjoying herself. After a few drinks, she started giving him a blowjob, and then I joined in. It was a pretty wild 3some, and I have to admit, it was kind of fun.