Yeah I feel like you're going to rationalize and justify this no matter what anyone else says. You see him as a romantic, talking about him "showering you with attention and affection", but the real fact is: he's carrying on with a relationship when he's LIVING with someone else! That's NOT romantic, sweet, special, or dreamy, no matter HOW you paint it. You're allowing him to manipulate you by clouding your judgment with his actions and words. Period.

If you were REALLY so "irresistible" and "special" and all that, he would have left his girlfriend for you. There is no "period of indecision and limbo". Either you love the person you live with, or you don't. And either you're amazing, beautiful, irresistible, and special, or you're not. It CAN NOT be BOTH.

I know you're not going to believe me, right now. But I promise you. Bookmark this thread/post and come back to it after things have ended with him, and you're going to agree with everything I (and several others) have said.

What you're doing is wrong, to the other girl. And you're allowing this creep to manipulate you. Just because you haven't given in to him sexually (yet) doesn't make this "ok" or "sweet" or "romantic". He is manipulating you emotionally and mentally, which, in many cases, is a great deal more harmful than using someone for sex. The things he is doing to you are going to take a LOT longer and be a LOT harder to recover from than if he was a one night stand, I promise. He is NO prince charming.