Personally Elana, I think you'd have a good time just being there. I've been to my last two uni may-balls (3rd one coming up...) with a good female friend of mine - we're both the only single-tons out of our group of friends so we accompany each other and it doesn't stop us having a fantastic time together, so I believe that if you wanted to go with your ex, then do so - nothing "more" (in whatever context you choose to interpret that phrase) has to happen
Ultimately, the choice is up to you - I know one of my friend's house at uni is all guys (none of them attached) and it doesn't stop them going to the ball without "dates", so with this aspect, I wouldn't worry about
not meeting any other, single, guys.
Equally, if you've got a group of female friends that are interested in going, regardless of whether they all have dates or not, then throw caution to the wind and ask yourself "heck - do I want to go?". After-all, as I've come to appreciate being at uni - it's not the uni or the course that make a place - it's the friends you make there
so if you
want to go, then I say "Go for it!". Life's too short for regrets and "what if?"s
Just some of my thoughts... for what they're worth
-Jackpot
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"lucky_jackpot is the smily god..." - gothicX
"Life is mostly froth and bubble,
But two things stand in stone,
Kindness in another's trouble,
Courage in your own"
("Ye Wearie Wayfarer" - by Adam Lindsay Gordon)