Those images of people who used to make us feel guilty are incredibly hard to get rid of, but since you realize what is happening, you will, hopefully, one day get rid of the image of your foster father. My T says that the first step is to realize that it is not your own judgment. Separating yourself from that image is the first step. Realizing that the image of the foster father is NOT you. It is not your voice speaking.

I do not know what the further steps would be - I am at the same stage you are at.