Tearsofaflower, run!

1. He never wanted a relationship with you
2. He is cheating with you on his real girlfriend (you are the other woman!)
3. He might have been cheating before, you just don't know about it - it's hard to trust this man

You don't need this, no one does. Forget about him.

P.S. 9 years is not a very big gap imo. The gap alone shouldn't have created such problems.