Aurora,
It sounds like you are on the right track by swimming and walking, that should make you feel better. I have asked the same questions you have and not understanding why the addict would do these things to me and treat me like he did. One important thing I learned on here from this forum (I believe Zoso said it) but sick attracts sick.
You don't want to be apart of that. You deserve better than that. He will only bring you down. I know it's easier said than done but try and stay strong. Another thing that helps me is keeping a journal. It helps getting all of that anger and negativity out.
Good luck and take care!