Super depressed and just a mess right now

I am 35 weeks pregnant almost 36 tomorrow,  me and my fiancé relationship isn't like rainbows and lollipops but it's good well I thought. I found out that he was on tagged (dating website) and he would reactivate it and then log out of it, then he downloaded a app called kik ( i guess so they won't have his number) I searched in his inbox. My first son father did this to me and left me on Mother's Day 3 years ago. My fiancé left yesterday and has been ignoring my calls and text. I tried to call his mom because normally that's where he would go but she didn't answer. My 5 year old son said he told him he will be back but he saw him pack a bag. We just started therapy for pre marital counseling last week, my world is crashing down. Last night I had a nervous breakdown like why would he do this to me after I told him all the hurt I been through and we only have 29 more days until our son is here. I seriously have no one to talk too, I don't want to talk to my family and I tried to talk to my cousin cause he knows him as well but he seems like he is on his side which is weird. I am religious person but now I wonder why did God do this to me put me with a man that will hurt me again. Sorry for this ladies but now i know why I'm so insecure because of shit like this. I am a very good person. I helped him so much when I had my taxes and when I have money and now he goes MIA.