I've been paranoid about my ex best friend and my sister for a while now. I got called paranoid by my mam saying that i'm acting just like my dad because he used to think she was sleeping with his friends behind his back and now i think my sister is sleeping with my ex best friend. I guess it's sorta the same situation except its my sister not my wife. The reason why this would piss me off so much and depress me is because i know what type of person he is and he will take sleeping with my sister as a huge ego boost and my ego will be crushed. It's really tearing me up. I suspected they were talking to each other and was called paranoid by my parent for it and now that they are shes calling me paranoid again for thinking theyre sleeping together. He turned up at her birthday with a card yesterday too.