<human>: So the other day I picked my girlfriend from school and she started to tell me how her day was. Well one of the stories was about how she touched this guys (who's a friend but also an ex) butt at school. 

But me being a "sensitive guy" it really hurt me hearing this, it pretty much put me in a depressing mood all day. So I brought it a up few days later saying that it really hurt me and that if I touched another girls butt she would be mad. She replied saying yeah she would be mad, but she doesn't touch people's butt to be sexual but because it's funny seeing their reaction. Even though this is probably true. This wasn't the response I was hoping for. I was hoping for a some kind of apology. So hearing that response really got to me...

Also I should mention that she does this to other guys that she's "friendzoned"  and she also does it to her girl friends.

Just making sure this isn't a bad sign to our relationship that may end up hurting me in the future. I trust this girl with all of my heart and know she isn't the type of girl who would cheat. But this really got to me so I came here looking for advice to maybe address how I feel about this to her. I don't want to come off as an overly jealous guy and upset her, upsetting her makes me feel completely awful. She's my first love so I'm inexperienced on how to handle these type of things.

Those wondering if the relationship is boring or bad. No our relationship is great! I love this girl, and I haven't been this happy since I was a child, and she always tells me that I make her extremely happy and she wouldn't want anyone else. We talk about the future together (college, jobs, even houses sometimes). We share many thing in common, gaming, anime, books, movies, and many nerdy subjects. We don't have any "major" fights just silly arguments and we always have a smile when we're together.

Give me a shortened version of the text
<bot>: Girlfriend touched ex's butt, should I be concerned about this or am I just overreacting because it's her ex?