No matter how hard I try

It seems that no matter how hard I try to forget, something or someone will always bring it up, not knowing how much it eats me up inside. I put on a smile, and act as if nothing has changed, but after it just destroys me.
I try to live my life forgiving people that have hurt me, that comes easy to me, the hard part is forgetting. I am good, until someone who has no clue what has happened brings that persons name up. I am not sure how to get over that. It just eats at me and makes me sick. Makes me sad, and makes me wonder if that will ever go away. Then the hurt, and memories come back and it is just a downward spiral.
I have tried to be happy, and not let it bug me. I know that my marriage is stronger because of this, but how much can one take of having the past come back over and over? I just want it to go away and I don't want to ever remember it again. I just want to go on with my life like it never happened.I want to be able to drive by places and not get sick to my stomach. And not hate that place. I feel as if my heart is numb, and that is why it doesn't always hurt, or maybe I have built a wall. I don't know I just know I hate feeling like I am going to explode if it doesn't go away.