<human>: Can you give me the gist of the text in a nutshell?

She and I met in college, had a wonderful, meaningful, happy relationship that lasted 5 years (the last 2 of which were 2,000 miles apart). I broke up with her 6mo ago since the distance was getting to me and I didn't believe I wanted to marry her. After a few weeks, I changed my mind and we were unofficially back together, but she decided after several months that she didn't want to be with me. It ended on amicable terms. We've had no contact with each other since. But I've heard through the grapevine that she's seeing somebody (whom I always disliked).

I found out recently that we're both attending a wedding in a month for our friend through whom we met each other. Several others in our social circle in college will be there as well. Everybody knows the situation, and for better or worse the friend has put us at different tables.

I'm pretty anxious about the whole thing, as I'm definitely not over her and this is entirely new for me. I figure I'll acknowledge her, maybe make a little small talk, and not get close with her, but it may be difficult/awkward as we have the same group of friends. We won't hook up.

I'd like some advice about the proper mindset to approach such a situation in which I'm not over my ex but have to meet her. I'd like to be as mature about it as possible.
<bot>: Meeting ex at wedding for first time in 6mo after serious relationship. I'm not over her. What sort of mindset should I carry?