What a nice little "line" he's giving you. This situation is wonderful for his ego, but not very good at all for your feelings or your self-image. It makes him feel quite important knowing you're still interested enough to ask - and he gets to enjoy a new girlfriend at the same time... You sound like a sensitive girl, you deserve a much better fellow. Consider leaving him out to dry - refuse to be the girl on the side and don't speak to him anymore. Period.
