Really upset :( want to cry today

Hi guys,

This seems so silly to me, I don't know what to do, last night me and my partner was talking about our past and I found out he has slept with 33 girls and he is only 21 a few of the girls I actually know :( he Skyped his ex without telling me back in Feb this year I spoke to his ex and she said it was just a friendly chat, why he not tell me then? :( , when we first got together he flirted with a girl and tried to meet her for sex they sent nudes to each other :'( I forgave him, he has messed loads of girls about in the past! He is great to me other than these , I mean I really love the guy we are engaged and ttc, I just can't get out of my head some of the things he's told me, and I've also read some of his old messages from him and other girls from the past! They keep repeating in my mind whatever I do!don't know what's wrong with me, please no hate... I had a mc 3 months ago, I lost my son when he was 2, 3 years ago. Life is horrible sometimes! I know I can't blame my man for things he did In the past.