Does anyone else have this and find it hard? DP has absolutely no interest in socialising with my friends, unless he has some kind of connection with them too, for example, someone we were both at school with. I invite him along to things, but he makes excuses or he will come to one thing - like an NCT Christmas get together (he is not DS' father, so didn't meet the other couples originally) - he came along, but on the way home said he wouldn't come to another one, because he didn't get on with the people there and they made him feel small
due to the fact the other DHs are all married, in their 30s, professional in careers with salaries, and (at the time) he was early 20s, working minimum wage nights in a hotel. The age thing has never been a problem for me with the NCT group, so it's not that they are stand-offish or set out to make him feel small.
When I ask him about this he just says that he already has friends and doesn't want/need any more, but I find this really frustrating and difficult to understand! I don't know if it's just because I'm a particularly sociable person and like meeting people or he is particularly solitary, or a bit of both. He doesn't have any friends who live locally because all of them are from uni, so are spread out quite a bit - he keeps in touch with them online, and he used to have a big party/get together once a year and invite everyone. One of them lives 30 minutes away so sometimes comes over or they will go out etc. I get on with his friends but obviously don't know them very well because they are never around.
I just find it really frustrating! He doesn't ever seem to want to meet anyone I want to introduce him to. Of course I know that not everyone can get on and be one big happy family circle thing, but I find it kind of upsetting that he doesn't even make an effort. When I tell him this, he just says that he does make an effort, but then immediately decides he doesn't like people. 
I know it is not just me, because other women I have met through having DS have said similar things, and if we ever try to get our various menfolk to meet up they are not having any of it! I suppose it's fair enough, but I just find it really hard to understand and tend to take it personally a bit, I suppose.