Me and my girlfriend were invited to a common friend's farewell party (this friend is going to live in another country). She does not want to go because some people I've been romantically involved in the past might be there. She says that if they are there and come say hi to me, she will feel bad.
I understand why it wouldn't be a nice situation for her to be in, that she can't control what she will feel and that I'd probably not be comfortable if the situation was the opposite.
However, to me, it doesn't seem right to lose an event just because of that. I made it clear to her that if one of these people approached me I'd just be polite and try not to engage in a conversation, but it wasn't enough.
I don't mind not going to this particular event (because we have another opportunity to see our friend before she travels), but I'm afraid this opens up a precedent and we end up losing something in the future.
I tried to be understandable and made it clear that I didn't think she was wrong to feel that way. All I asked was that she give it some thought and didn't blind herself behind the "I feel that way, so I'm right to avoid this situation" argument. She got mad because I was "questioning her about what she feels".
How can I approach her to see if we can change this in the future? Ideally, I'd like to help her deal with her feelings instead of avoiding them and losing opportunities to be with our friends.
Background: We are both in our early 20s and we know and dated each other since we were 15. We have broken up twice in the past (for several months), and I was with those partners (short) before we started seeing each other again.
She believes that some of my past partners will be there because they are friends with our common friend (we are part of the same large group of high school friends). AFAIK she did not have a bad experience with them specifically.