My boyfriend has been hanging with girl that is known for always hitting on taken guys. At first I just mentioned how uncomfortable it made me, but I tried to just get over it. Then one day she starts telling him how she's a biter and she's a sadist, and then she apologized saying "sorry I get horny when I'm bored." My boyfriend didn't reply to her, but he invited her (and one of his guy friends) over to his house not even a month later. He says he understands why I'm so upset over it, so when I asked if he could just not actively try to hang out with her he said, "The other day she told me how she's a loner and she needs friends, and I feel like me inviting her over was me kind of saying to her, that she doesn't have to be a loner." He says he doesn't want anyone to put a wedge between us. I don't know how I'm supposed to feel. He's the first serious boyfriend I've ever had (Three years) and nothing like this has ever really happened before with him. Am I overreacting? Am I being naive?