<human>: Provide a brief overview of the text.

We've been together about two months now. I've always felt a little off about the guy but nothing too crazy. Long story short she tells me that she use to have feelings for the guy years ago. That alone really wasn't an issue for me. But she also wants to spend two weeks backpacking with this guy in Europe. There good friends and talked about going before we got together. Am I crazy for not being okay with this? 

I'm thinking about just breaking things off with each other if she goes through with it. It's not fair for me to tell her not to do things, but it's also not fair to put me into this position. Of course I plan on talking with her before I go to that as an option. 

This sucks, this is a really great relationship other than this. She really is amazing and I'm also not mad at her, she has nothing but the best intentions and I know she really doesn't want anything with this guy. BUT, life isn't that simple and things happen and I see this becoming an issue for us as a couple in the future.
<bot>: Vacation with a guy friend she use to have feelings for. Am I crazy/10 for not being okay with this?