Finding out he is cheating

So one minute I am so excited about being pregnant the next I get a text of my boyfriends ex saying he has been cheating on me.

I am now 5 wks 2 days and devastated. He is saying he wants to be with me but how can I believe him now.

So stressed and worried sick I will loose this baby because of it, I can’t sleep and just can’t think. Heartbroken when I was so excited 😢