<human>: To preface this, I've always thought of myself as a person immune to jealousy. I've never been in a relationship where I felt like my SO would cheat on me.

I don't think my girlfriend would cheat on me. However, she has cheated before (on a different guy), and that is sometimes in the back of my mind. Moreover, she was polyamorous before we met and began dating. Sometimes, I can't help but feel like one person's attention will ultimately not be enough for her. 

Regardless of the above, I feel like I do a pretty good job of rationalizing away my insecurities and not letting them affect me. Lately, however, I feel like I can't go a day without having to hear her tell me about all the men and couples who have tried to have sex with her. 

This issue came to a head two days ago when she asked how I would feel about her going to see a concert with her first serious boyfriend, with whom she has maintained some contact through the 5 odd years since they broke up. The guy offered to pay half of her costs to go see a concert 1000 miles away, stay at his house, then fly back. She told me she really wants to go. I asked her to give me some time to think about it.

Last night I let her know that I was extremely uncomfortable about the whole thing. I told her I was somewhat hurt that she didn't immediately dismiss the idea as a bad idea. I tried to explain that there are some pretty obvious boundaries regarding exes that people follow. Her response was "fuck boundaries" and that boundaries are a way to control people. Then she was upset that I thought she was so stupid that she didn't know what boundaries were. 

I feel completely disrespected, hurt, and I'm worried by the fact that she wants to go spend a weekend with her first love, when its only recently that I've begun to feel that I am in love with her. Is there another way to think about this? Are my feelings about this reasonable?

Give me a shortened version of the text
<bot>: GF wants to go visit her ex-BF 1000 miles away. I don't know how to respond in a way that gets across that her doing this would be extremely hurtful to me without seeming like a controlling jerk.