This is a clear case of jealousy. We all get it when someone we care about seeks out the attention of others. It makes us feel like we are not enough for them. Makes us feel used. As crass as Billie’s advice is, she hits on a truth about people. We are all motivated by complex things in our past, so it’s hard to know what drives Tan Man. There are people who try like hell to get other people’s attention, but they don’t really want to stray from their loved one. It’s an insecurity. Then there are those who believe they will never be “owned” by another, that their journey in life is to engage with others as they see fit, regardless of how it makes our partner-of-the-moment feel. All you have is your gut feeling. If you think he’s using you, (and you don’t mind a little of that), treat it like a short-term adventure that has great handles, then move along when you see something better.