Megan, 25, from USA, asks:

I've been dating my boyfriend for 15 months. Things are pretty good, but we have some bad fights and we're in the process of going to couples therapy and working through our problems. He seems very committed to the process of improving our relationship, and to me, although I have trouble trusting him. It's like there's a little voice in my gut nagging me to not trust him.

Anyway, last Thursday I invited him to my friend's party. Right after he got there, he started talking to a pretty girl and talked with her the WHOLE night. I came over and introduced myself as his girlfriend and she was very friendly and fun to talk to. Then I left to go talk to my other friends, and he continued to talk to her. He spent probably 2 hours talking with her before she left. Afterwards, we talked about whether he (and I) wanted to be friends with her, and he eventually came to the conclusion that he didn't really need to have a girl friend (i.e., friend that is a girl). But this morning, I checked his text messages on his phone and found that he texted her saying 'Very nice to meet you last week'. After I saw this, I asked him whether he wanted to be her friend, and he said 'Not really'. He did not know I read the text message. To me, this seems like a sign that he's looking to cheat. Am I paranoid?

VictorM's advice:

No, you're not paranoid. He has sinister intentions. In fact, that he told you he didn't want to be her friend, when in fact he enjoyed her company, sounds even more suspicious.

If this was a one off, maybe you should give him the benefit of the doubt. If he had mentioned the text message to you, it could easily be considered simply a polite gesture. But it seems from your own words that you've had reason to distrust him in the past, so his behavior warrants suspicion.

Listen to your little voice -- it's seldom wrong!