<human>: Can you provide a brief overview of the text?

Ok so here's the story me and my gf of 2 years invited me to her male friends birthday party, and a friend she slept with once [24M] will be there. 

it's a few days before the party and she tells me not to respond to him if he makes any Jerky comments towards myself. I was a little confused about it at first so I asked what she meant, and she told me that he was planning on "testing me"  to see if I was "a cool guy or cried like a Bitch"  now after hearing about this I really don't want to go anymore. 

 I was teased allot growing up, and ever since I try to avoid most "bro down"  situations, because frankly I don't want to bother with having to avoid the guy the entire night.

 I'm at a cross road because the gf really wants me there, but I always remember that if I don't want to have a problem I avoid the potential problem starter altogether. Am I over thinking this or do I have a point? If I do end up going, I could use some tips on how to handle this situation.
<bot>: bro down at a party, I got a heads up from my gf not to have a reaction to it because I'm being "tested"  am I unreasonable for not wanting to go because of said "test"?