I think it's fairly cynical and fairly patronising to assume that she will think all relationships are like this. She has eyes I presume, and ears, so is capable of observing and talking to other people about their relationships, therefore I doubt she is as Babe in the Woods as you assume. She might well have fallen for him, that's a common issue with f*** buddies, one person becomes more involved than a other sometimes to devastating degrees but the only people who can sort this out is them, there is no freeing to be done, she's free already unless she doesn't want to be, and it sounds as if she doesn't. He's not a cad, he's a friend with benefits so unless hes lied to her face and plighted his undying troth to her he's done nothing wrong, she's just perhaps become too needy and involved. I don't think it's abusive, I think it's unfortunate, but it could just have easily been him who was besotted and her who couldn't give a damn, the no-one would be crying abuse. If it was my relationship I'd simply be furious if anyone interfered.