Growing up I was never really close with my younger cousin although we were always around each other. As I grew older I decided to actively pursue a relatiosnhip with her and despite our differences in personalities I hoped we would become close. I invited her out and brought her around my friends. She ended up developing a close friendship with my partner. I quickly became uncomfortable with their friendship because they would text and video chat a lot. Once I expressed that I wasnt comfortable with how much they communicated my partner shyed away from the friendship but they still talk here and there. 

Fastforward to now my cousin and her live in boyfriend broke up. She called my partner hysterically to vent and gave my partner details about what happened. Not once did she call me or share anything with me. She then asked my partner to stay at her place the first day her boyfriend moved out because she didnt want to sleep alone in the apartment. My partner inisted my cousin meant for us both to sleep over however not once had she communicated with me. Eventually, my cousin asked whether my partner had spoke to me about sleeping over. When I said that my partner told me she wanted them to stay over she said it included me. After that text I never heard from her again ( which to me means I was never really invited). 

I feel angry and disrespected because I feel as if she doesnt respect my relationship and doesnt understand boundaries. My partner insists that I should try to be understanding because my counsin's world was just shattered due to the breakup. I was also asked to keep in mind that my cousin is a very juvenile person. I'm not sure how to move forward with my anger. I dont feel any sympathy right now and dont believe that addressing any of this with my cousin would help the situation in any way.