<human>: Can you provide a brief rundown of the text in within 3 sentences?

Earlier this year, I moved to the other side of the world to be with my partner. It has been fantastic and a learning experience and we are both very happy. Here's the 'but': He has A LOT of friends which can be segregated into two separate groups. Group 1 is a fairly large, close-knit group which I absolutely love, we all hang out pretty often and have personalities that mesh well. However, Group 2 is a different story.

Group 2 is a separate close-knit group whom he met through his last girlfriend. They ended on good terms and are still friends, and he still hangs out with the group often. Sometimes she's there, I guess I'm okay with it as he insists they weren't ever very 'close' but I feel awkward most of the time. They're younger (early 20s) and a lot less mature. When hanging out with this group, they always bring up things that happened while my partner and her were together several years ago. Obviously this is before me and I often feel left out and pretty invisible most of the time. The last party we went to, I was the subject of the conversation as I was standing right in front of them... I don't understand why they talk ABOUT me instead of getting to know me while I'm there. Maybe I can't contribute to their group, I don't know. They wouldn't be the type of people I'd hang out with normally, unlike Group 1.

We have a Halloween party coming up with Group 2 and I really don't want to go. I don't like hurting my partner's feelings by saying I don't feel like hanging out with Group 2 much, but I honestly don't feel comfortable and I don't exactly enjoy hanging out with his ex-girlfriend (personally, I find her to be rather irritating along with the rest). I want him to see his friends, but I don't want to be there.

Not sure what to do. Any advice? :(
<bot>: My partner (24M) still hangs out with his ex-gf and all of her friends and I feel awkward being there and don't want to anymore.