I need to vent

I've been with my boyfriend for three years. he's cheated on me twice and I made the decision to forgive him. we ended up getting pregnant in December. he was happy and wanted to get married. he himself was googling and making plans. At the end of March I had a miscarriage. Now the talk of wanting to get married puts him on the defensive. he get mad and starts a fight and comes up with all these random excuses then gets mad when it upsets me "because he's not saying no". I've forgiven this man for stuff most wouldn't, I've accepted his child and have loved him. I've put up with his crazy baby mama who tries to come between us. and I still love him and would marry him tomorrow in jeans at the courthouse yet he says he has all these reasons in his head (that he won't share ) so he can't commit to anything even a future date or anything but he does want to marry me at some point. I feel like I'm wasting my time and that I'm just not good enough I know this is long but I am sitting in the bathroom crying alone and really needed to talk to someone and vent