I'll try to make this as short as possible.
My grandparents have 2 kids. My dad and a daughter. My grandma has always picked my dad, and my grandpa has always picked my aunt. My aunt is causing all kinds of drama and has essentially torn the family apart. (She has told her mother that she doesn't want her to ever see her kids again, won't let her mother take her kids anywhere, calls her a bitch, etc. etc. etc.) (All because my dad's wife is in the picture now.) Well, one day a few months back, my aunt and grandma were arguing over email. I sent an email to my aunt on behalf of my grandma because i thought the email would upset my grandma too much. Lots was said, lots of not nice things, from both parties. Aunt's son's birthday party happened, and I was not invited. My grandma called my aunt to ask if I was, and aunt told grandma that the family issues are grandma's fault and shes a effing bitch, and that I (me) am a sassy little bitch.. or something to that effect.
My aunt had received a save-the-date before this happened. (the issues are long standing, now, 4 years or so). Now, I'm stuck because I don't want someone who will call me a sassy bitch to my grandmother (and forward the email to my grandfather) at MY wedding. Not inviting her would crush my grandfather's heart. Her presence would make my wedding hell. (Destination wedding so she might not even show up). I don't know what to do. Is uninviting her and further destroying the family worth it?