I recently found out that my husband had been chatting for a while with a good friend of mine (female) through Snapchat. My husband and I are friends with both her and her husband (she is married too) and we hang out with them and another couple often and we all consider each other good friends, but she has been my friend since before I met him. This past weekend, we went out to dinner with her and her husband, and when she had a second alone with me she said she kind of wanted to come clean about the fact that she'd been talking to my husband through Snapchat quite often. She was pretty tipsy at this point and played it out like it wasn't a big deal, was just casual conversation but that she felt she needed to tell me. I asked my husband about it the next day and he said it was just 'bullshitting' and casual messages sometimes like "hey whats up," etc. However, he did say he realizes it does not sound good and he apologized and said he asked her not to send him any more messages through there. But I can't really get it out of my head. The fact that they were talking often and I didn't know. And the fact that it was on Snapchat, an app where all messages and pictures are deleted permanently after sent and viewed. It feels very slimy, and I can't shake being upset about it. I kind of just want to get some other thoughts on this, and ask what others might do in this situation?

Thanks