Cheated on while pregnant

Okay where do I even start I'm 30w 4d pregnant with a little boy I'm 18 and have just moved into my own place with my partner of 3 years and also just lost my job but for the past few months he has been acting not himself he has been treating me terrible every time I talk I get told to shut up and I'm annoying him he won't have a serious conversation with me and is constantly on his phone ignoring me and always out a few days ago i found out why he has been going to the clubs when he said he was with his family he hooked up with another girl there and got her number and has now been tecting her for the last month he even told her he had feelings for her I asked him and he denied everything then finally told the truth only because I already knew he says he is going to change and that I should give him a 2nd chance and that things will be back to the way it was when we first met he said he's not going out anymore I took away his phone and blocked numbers keep calling am I crazy for taking away his phone? He says he loves me and wants to stay with me and doesn't care for her he said he is sorry and doesn't know why he did it but I can't help think he's only sorry he got caught and how long would this of gone on for if I dident find out also I'm worried he did more than just hook up with her but he won't tell me I feel like he betrayed me and out son I feel worthless I don't know what to do right now can someone please help me the worst part is is that I still love him and want to have a happy family with him but I just don't know if this will happen again or if he will just start treating me like shit again and going out all the time when my son is born I really need advice on what to do right now please comment 😔