Not sure what to do...

Okay so my husband had this girl friend who he met a few years before us getting together and they talked on and off until one time I seen their conversation and it was about her sex life and how terrible it was and how she was jealous of me because I have my husband so I told him I was uncomfortable with them talking so fast forward several months I saw a name in his phone with the same last name and I didn’t read the message and he then told me it was this woman’s husband asking him to play soccer so I thought ok whatever then fast forward again to last week this “guy” was in his phone again and come to find out it’s THAT WOMAN.. he put her in his phone under her husbands name. They were talking about how he cheated on her and my husband told her to leave him once again and then proceeded to tell her I’m heartless? For literally no reason. Last year at this time I was pregnant and he had a few girls in his Snapchat he was talking to that I didn’t know and one was a girl he met right when he met me and every time he’s initiated all of these conversations.

What the hell would you do?

Am I overreacting?