Hmm WTF! Better not be what I think it is!?

This past weekend my bestfriend and I was hanging out well we went to hang out with one of our friends my ex ended up being there he was my first boyfriend so we still flirt and I think we got some tension between each other. Well we was all sitting on the couch watching movies and my bestfriend and my ex are writing each other on facebook handing each other the phone like they was talking about something I didn't ask but I think it's messed up for her to do that I'm not talking to her or him cause I have a feeling they wanted to hook up and wanted me out of the room. Am I wrong for being mad or is it messed up on her part?