Nope, she's not cheating on her boyfriend. He's probably the guy who's idea it was from the beginning. If you find her attractive, its probably the way they planned a threesome. Sick freaks who want to watch their girlfriend or wife have sex with other men. I never heard of something so freaky until I married a phycopath, I divorced. He wanted control over every aspect of life, including my body. He me off to other me, so they could see and experience what he had. His fantasy became more demanding. I was not about to fill and ended the marriage. He'd start by saying, crawl in bed with male quest, show them you body, flirt, let them touch you and once I got him going he would join in and watch or join in too. No wonder he has been married a dozen times and counting. If I were you throw, her nasty butt out of your bed before you get a STD, or regret having ever getting I involved. Only babies or young children crawl into bed with their parents. If she's over 7, she's fully aware of what she is doing.