My ex and I broke up about 6 months ago after a three and a half year relationship. We've remained friends since then (Our relationship was the result of a three year friendship, so not being friends would have felt strange). Although our friendship post break-up consists of talking on the phone with each other but we never hang out. We've seen each other about 4 times after the break up in person. I hadn't seen him in a while and am throwing my birthday party tonight. I had invited him as I'm throwing a big party with about 30-50 people and decided to tell him about it since we were talking about my birthday on the phone (would have been weird to not invite him to it.. )
So I felt pretty good about it, I had stopped thinking about him and never regretted the break up (The break up was on my part, because of our young age (20s) and the fact that I couldn't picture marrying him in the future I felt it was a waste of our youth to stay in the relationship. Especially with him since he was very much a hermit and didn't go out much. But, although we broke up and I felt it was the right decision, we were still in love when we broke up. It was done mostly through reasoning, but was definitely necessary.)

Anyway, yesterday I went to an event, and he was there. We spent most of the time hanging out together, which was nice but a little difficult because it felt like we were a couple again. Especially because everyone at the event had known us as a couple and mentioned the break up a few times. Not to mention that I'm still attracted to him and I know he is still attracted to me so those feelings came back when we were together again. At one point an old friend of mine came over to talk to me and he asked me out for lunch in front of my ex, which he clearly didn't like.
Anyway, leaving my ex felt like another mini breakup and I felt pretty depressed coming home. Now I'm worried about my party tonight and am regretting having invited him. I feel like it will be difficult for him to see me talking to guys and for me to see him talking to girls and knowing that we both can potentially go on a date with one of them.
I really want to just have a good time at my party but I really feel like this may put a damper on it. I don't want to end up not having a good time or crying or anything especially since it is my birthday! I'm considering uninviting him and explaining why. I feel he would understand but it may make it more awkward afterwards when we see each other and I would feel bad having to tell him to not come to my party so last minute.. Would that be really rude? Or should I just suck it up and dodge him at my party?

Thanks!

Although you two may have been friends before your relationship, and want to remain friends now, that may not be possible immediately after the break-up. I would suggest distancing yourselves a bit and give both of you time to get over each other. Maybe after a year or two away, you will be able to rekindle a friendship, but it sounds like it is too soon to do so now.

Not only would it be rude, but selfish and unfair. You both have to realize that the mature way to deal with this dilemma, is to have a good time at a party, with everyone.

My gosh it's a party, not your own personal soap opera, so don't make it one.

Plus its your party, and you do have to mingle. So don't assume he can't handle it because you are so worried. He is a big boy now, and can fend for himself, or decide on his own, not to come.

Relax!