cheating husband

My husband had an affair for several months that I knew nothing about. When I found out he ended the affair. More recently after a period of several months since he ended it, she began stalking him. (See my discussion on that). The stalking seems to have stopped now. I am still with my husband but it is very difficult to pick up the pieces because I will never trust him 100% again. I have to trust him somewhat and forgive, otherwise it would eat me alive, like a cancer. But I can't forget and it has damaged our marriage.