What would you get from marrying him? I don't know the laws of your state but without the marriage there is still child support, etc. I would have a discussion with him, why he wants to marry (does he think that's what you want or that that will help you trust him more?) what he sees marriage as being like, etc. If he is trying to help himself stay on the straight and narrow because he believes the idea of being "married" will mean something to him, I'd say he is trying to use you for his own benefit rather than be a partner to you, which is what marriage is about to me. My husband and I often say/notice what a "great team" we make. I say don't partner with a donkey if you are a race horse!