<human>: Can you condense the text into a few key points?

I am a 28 year old male and have been dating my girlfriend (25F) for a little over a year.  A few months into our relationship I found out that my gf's ex boyfriend from college was texting her late at night.  To my knowledge it only happened once and she made sure it stopped.  She had remained friends with him after they broke up, but stopped the friendship after she found out I wasn't happy about it.

Her ex is still friends with all her good friends.  I found out a few days ago that she was invited to a wedding and he will be there.  I know he will be talking to all her friends and I'm sure I'll be forced to meet him.

To be honest, I don't even want to go to the wedding because of this reason (i realize this is not rational...).  I truly hate this person only because he dated my girlfriend and texted her late at night once (again I realize this may be irrational).  I think about it everyday and it pisses me off.  I have no desire to meet any of her ex's.  We have a great relationship and love each other very much, but that still doesn't change my mindset.  I have a past as well, but I'll never see any of those people again, fortunately.  I just dont believe in remaining in contact with my ex's and luckily I have no common friends with them.

Thoughts on dealing with the situation?  I don't want to take this out on my girlfriend.  I always want to support her, but it's just bringing me down thinking about this wedding.  i dont want to act irrationally at the wedding either.
<bot>: my gf's ex bf will be at a wedding i have to go to.  i hate this person and never want to meet him.  worried i will act irrationally at the wedding.