My OH is messaging a girl he’s met on Facebook. I feel awful for checking my his messages on his iPad but he’s been a bit secretive about a group he chats with people through and I got curious. They message quite late at night and are flirty and occasionally quite sexual in the language they use - although in a jokey manner. Sometimes he talks about our relationship with her - things he doesn’t talk to me about and he often asks what she’s wearing. She often in a roundabout way suggests he should look up train times to visit - although nothing direct. He mentions me in his comments so he isn’t hiding our relationship. The group he met her through are all quite rude (apparently that’s funny) to each other so I think if I confront him he’ll just say it’s oart of that type of ‘banter’. Am I wrong to think this is just not ok?? Am I being a stupid cow not confronting him about it??