You mention OCD is a factor - When were you diagnosed and are you being treated? Actively receiving treatment can make you more able to deal with the challenges life throws at us, especially if you were diagnosed more than 10 years ago. Treatment has come a long way for OCD.
Being polyamorous does not mean he'd change a single thing about you. He's with you because you are appealing in a variety of ways.
If I say anything else, I'll just be saying the same stuff already said, but welcome, and hope you'll stay.