Its possible he isn't poly, sure. It doesn't really matter what the terms are though. The fact is he broke up with you. Now you'll have to move on some how for the sake of your child and yourself. You are free to go about anything you want in your relationships now without consulting him about his boundaries. That's tough I would think to adjust your mind to being single again and yet still have him as a friend. You have every right to grieve. You'll get throught it though.
Anyone want to be friends on Facebook?
Send me your name via PM