I have something simple to say. Assuming anything about people's motives is not a good idea. My example is MLC25's story about the homeless man. She thought he was talking about her and he probably was not.
There is a concept of inappropriate guilt. I do not know what your story is exactly. But I do know you feel guilty. If you did things that were horribly wrong then I understand your need for forgiving yourself. You can also examine if you did these things then what is appropriate to fix them in the future and apologies for the past. That would be just for you.
For me I never ever to my inlaws spoke one bad thing about my ex. I told them my story without recrimination and we have a good relationshop to this day. Whatever he told them I have no idea. Moving forward in this manner might help you. But in Barb's camp, can't forgive what happened, on the other hand in some ways I do. People are not perfect, none of us. That is how I found my peace. Wonder