Dad wants back in the picture

My husband left me 3 months ago and we filed for divorce. He abandoned me and my 2 old and I’m 19 weeks pregnant. He tells me today that it was all because of his mental health that he left me but he wants me back and wants to get help. I have been a single mom for 3 months and had to completely rearrange my life to figure all of this out and I’m so confused with what do to. I know he was manic depressive and borderline bipolar but that scares me that this could happen again. He is coming over tonight to talk and I’m so confused with what to do and I don’t want to be hurt again. Not to mention I made the mistake of finding a rebound so I have been seeing someone for the last month. 😢