We're seeing each other and I know we're in love but she has a boyfriend?

Dude. Don't go messing around with another man's woman. It's only a physical feeling she has with you. If she feels so strongly about you, she has to leave her boyfriend first. It's the only way it'll make it right. She has to take care of herself and her boyfriend before she takes care of you. If she does break up with her boyfriend, then you're both good to go. And if what I'm saying doesn't convince you and you still want to sleep with her while she's in another relationship, then think about this: everytime you kiss herlips and mouth, you're tasting and kissing her boyfriend's di(k. And if you do have sex and you go down on her, it'll be like going down on her boyfriend because he'll probably have been in there recently. It's gross, isn't it?