Why am I feeling this way?

Im going out with this guy and im happy with him and he's awesome but my ex is dating 1 of my best friends she like my older sis and everytime im around her and she txting him I get soo mad and have a ton of mixed emotions and I know I don't like him because I broke up with him and plus when we were going out I didn't really like him and I got my "sis" and my ex together but why am I having mixed emotions??? Any advice will be awesome thanks!!!

Change you emotions. This can be a good company, where everybody know and like everybody. See this side of the situations. You can wink to all the members of this company.