Baby daddy cheating???

You guys I need some advice. I’m so hurt. I’ve always had a bad feeling about my boyfriends ex. I just had a feeling that they were still seeing each other or something is going on between them. He always told me I was crazy for thinking that. Well this feeling just won’t go away so when he was brushing his teeth this morning I went through his texts with her. (I never go through his phone). I remember going thru it around Halloween time and he was like “I can’t wait to see you in that costume again😁”. And they do share two kids together. And I confronted him about it and he brushed it off and was just saying it was a joke etc. so I was like whatever but this feeling hasn’t gone away so I checked this morning and he had sent her a picture of herself and was like “you’re makeup is perfect you’re beautiful!” And I didn’t get to see what she replied with because I heard him finish. But I knew deep down there was something going on. I just need someone to talk to I feel so hurt and betrayed. We’ve been together for a year and a half and I’m 28 weeks pregnant with our son. I had my glucose and ob check today which I ended up missing because I feel so flipping hurt. This is also a hard week because Saturday will be the 1 year anniversary of my brother committing suicide. How do I approach him or what do I say??? Because right now all I wanna do is scream and cry and bash his windows in. He also doesn’t get off work until 6. And I wannna text him and flip on him but I know it’s better to talk in person... any advice would be so appreciated😭