I had my sister call me up the day of my niece's bday party to ask me if I was bringing my daughter. I told her that I was. She told me she was calling to make sure there wouldn't be any trouble. I asked her why there would be trouble and she said that our close friend Tina was going to be there. I said that I don't have a problem with Tina does Tina have a problem with me. My sister told me that Tina doesn't have a problem with me but that she is together with my ex husband. I feel she crossed a line between friends. They think I still have feelings even though we haven't been together for 4 years and I've been with someone else for two years but me and my ex were still friends. I feel like a line was crossed by Tina. I feel like my sister should have told me sooner. And I feel even more betrayed because I found out that Tina and my ex went to my sister and asked her if she thought that they should tell me about their relationship and my sister said not to tell me. Now that I confronted them about how I felt betrayed they made it out like I'm on some high school bullshit. Do you think I'm trippin?