Unintentionally being the other woman.

I got into a relationship over a year ago with a Man who as far as I was aware was separated.. this turned out not to be the case and I only found out the day he left his wife for me. His Ex makes life very difficult for me with horrible names etc and with his two kids, because she thinks I knew all along. I want this to stop but idk if bringing it up after all this time is gonna just make things worse?