Cheating or no?

I found out my husband has been texting another married woman. And I mean a lot of texting. Talking on the phone for 30min at a time. He never told me. I looked in his phone and he has it saved under a mans name. He claims it was nothing and it was just friendly talk. I contacted her and she assured me she's happily married and it was nothing. I also found out today he called a trac phone set up number. Am I over reacting?