My bf have a secret snap that he isn't telling me about. A woman told me they are dating

I'm 33 and have been dating my bf for 3 years. He has been ok during that time, but doesn't seem super in love with me. I've been working on things but have been thinking about moving on.

This week a woman reached out and told me that she thinks she is dating my bf. She said he told her he was divorced and that they only meet on weekends (that he doesn't have the kids. He has no kids). She found my contact information and showed me some texts. I don't know that I believe her though as she didn't have any pics. She said they only used snap and didn't take any screenshots. She said she blocked him now.

Is there a way I can confirm he is cheating? Even if I break up with him, I want to know the truth.