Thanks very much for the advice!
I think in the end, rationally, I know that I am loved and atrractive to my partner and that it shouldn't really matter if other people are 'more' attractive.
I think I just needed a chance to be told that. No matter how many times you tell yourself something, I find it's always more believable coming from someone else.
Galagirl: They weren't celebrities, they were people we know but they are so out of reach that they may as well have been celebrities.
I get your point and I think that probably has a lot to do with it. When it's someone far off it seems less 'threatening' so to speak that they are more attractive but this girl is a friend of his whom he used to be closely intimate with and still wants to be. So it's a little more close to home.
I'm not bothered about him being attracted to other people, it's the 'more' that's got me all weird.
I think I just need to sit down and have a long chat with my ego to straighten things out.