Should I stay or go

I’m lost! I know the easy answer would be to leave but I love this man and am 5 weeks pregnant with his child. Soo I woke up this morning and had a dream he was cheating on me via Instagram (which he deleted almost 3 years ago). I go online and the account was back 💔 It cut like a knife. We had an agreement not to have Instagram over issues in the beginning. His idea! He swears he was just going on to get pictures and that’s it. I don’t understand why he wouldn’t have just told me that then??? I’m the beginning he lied and an ex (he was still in love with). The first 2 years he lied and talked to other girls a lot but I thought we were over this!! I told him give me the password and he did but first he deleted all the messages on the account. He always make me feel like it’s my fault when he clearly is in the wrong. Yes I have trust issues but HE GAVE THEM TOO ME. I just wish I had the strength to leave! He will never change