secret online relationship for 2 years

K so my now ex and I met when I was 18 and he was 22...we were together for 4 years and recently broke up. We had gotten engaged, had our daughter who is now 7 months old, almost bought a house and I just found out i'm 2 months pregnant with our second. He had some issues in the past where he was doing some things i didn't like and i considered disrespectful (following half naked girls on instagram, going to his friends houses who were girls) that kinda stuff...we found out i was pregnant again on a monday...on the wednesday i had a gut feeling that i had to check his phone, and when he fell asleep i did and i found out he was having a secret online relationship with a girl for 2.5 years. He told her he left me because i was using him for his money, house and truck. When i confronted him about it he said he stopped talking to her a few months ago, and i wnded up leaving him. So now, i'm a single mom (pretty much he works crazy hours and always has) he says he will help me financially support them but is also begging me to take him back...he says he will do therapy and counselling and will never do this again and make me regain his trust and prove to me he will change and be a better man.

I want to take him back so bad, i want us to be a family...but i feel like if i do he will do it again, thoughts? i've never seen him so upset. he was on his knees begging me to take him back and he's been begging me every day to see me and our daughter even for a few minutes, says he doesn't want anyone else but me and he says he won't stop trying to prove it to me.