What does this mean?

I was hanging out with some friends yesterday and significant others got brought up and one of the guys said yeah kinda but we know he has been dating this girl for about 2 years and one of the other guys ask for clarification by asking if he had multiple girls or just the one and he joked about having multiple and made r seem like his relationship with the girl wasn’t serious but that’s different from how you would expect someone in a 2 year relationship should act about his girlfriend when she isn’t present. I don’t know if he was trying to make a certain type of impression on the new people he was meeting. I know his girlfriend and she is super sweet but I don’t know what to do. Can anyone interpret this?