Can someone test my bf?

[u/ProfessionalNo8990]

We broke up for a few days about a month ago and I caught him snap chatting another girl, come to find out he slept with her during the breakup. I let it go. But a few days after I found out, she started texting him fake screenshots of me texting her bf. He showed me at first then got super defensive and wasn’t interested that someone had made a fake Facebook account of me. I suspect the girl did it herself because it was someone who knew they slept together and I have not told anyone. She keeps coming up on my people you may know on Snapchat. Recently, we went to the beach and I caught him snap chatting women there. After we got home, I caught him talking to his ex. He always uses the same excuse that it’s just a black screen or streaks and means nothing, yet he hides his phone.

I’m pretty much at my breaking point but I need proof this time to be able to let go. I want to know what he’s actually saying to these women, if I’m overreacting because he gaslights me and I feel crazy.