Before I met DH, he had a pretty bad break-up with a girl that resulted in also losing a close guy friend. (the guy friend's girlfriend was best friends with DH's ex).
All the time I've known DH, his guy friend has never been around. DH told me once about how he thought maybe the guy was mad that DH and the ex didn't work out, since the guy's girlfriend was best friends with the ex, and maybe things were awkward, so they stopped talking to DH.
Fast forward to tonight. I come home from class, and DH comes home late. Apparently the guy friend had called out of the blue, and he went out to have dinner with him and the guy's girlfriend (now wife), and one other guy friend from their old gang.
When I ask how things went, DH is very quiet and doesn't say much. He almost doens't want to answer questions. I ask him if he thinks he and the guy friend will be hanging out again now, and he doesn't know. He doesn't really tell me ANYTHING, which is out of character. Usually when he meets up with friends, he tells me afterwards about how they're doing, what's going on in their lives, everything.
This time there was nothing, and he kind of had the shifty conversation thing going on with me, where I could tell he was trying to avoid telling me something. Words weren't flowing from him as casually or as freely as normal.
I tried to shake it off as maybe he doesn't have much to say about it, but he was gone for 2 hours, and he's never acted this way afterward. So then I wondered if maybe his ex had something to do about it (like maybe it was brought up?). But even then that's nothing to be shifty about.
But then I wondered if maybe she had been there? (after all, she and DH's friend's wife are best friends) That MIGHT explain why DH is being wierd about the whole ordeal.
I tried questioning him more about it, but he seemed intent on going to sleep, which isn't all together too unusual, since he has to get up around 3:45 am for work (he works on New York time).
Am I overthinking this? I'm feeling really bothered about this.

Re: Feeling a tad insecure
I don't know if I'm necessarily the jealous type if DH was up front about it. I've never been in a situation to meet an ex of his before. He keeps them so far in the past that he doesn't like talking about them much or having anything to do with them. Only reason why I know so much about this girl is because he was kind of "damaged" by her a bit when we had first met.
I think what's making me worried is his attitude, and not necessarily her "presence". I've dated guys before that are upfront about exes that are still around, and I've always followed the idea that as long as the guy is acting good, then I'm okay.
Edit: Additionally, one of DH's closest friends is a girl. She was his prom date too and everything in high school, and he's super up front about her and she and I get along great. So I think that if DH is honest with me and he's acting like everything's fine, then I'm fine with it.