Big mistake 😢

I put babys dads last name on his social security. I also out it on the birth certificate but since he was not present they couldn't file it until he is there. I really don't want him to be on anything anymore because he is so rude and so disrespectful. Before the baby was here he wanted absolutely nothing to do with him and now all of a sudden he wants to be here and telling me what to do and how to take care of my son and just making me feel absolutely terrible about myself any chance he gets. He even carries the baby and tells him "your mom is a stupid bitch huh".. We stay at my moms house and he is so disrespectful to her it's disgusting. even after I confront him he doesn't give a shit and he will just make me cry instead of apologizing for being so rude. He doesn't contribute anything but has an opinion about everything. I can't take it anymore. .. I don't want him to have any rights to the baby because I'm scared he's going to try to take him from me as he has threatened before. I don't want to take the dad away from my son but he is so toxic. I wish I had gotten out while there was still time.. I sit in a blank stare most of the time just thinking and fighting back tears.. I don't want this in my life anymore... I regret being so hopeful. I hate this.. I'm just at a loss and I don't know what to do.