Hi Lance.
I have not done step work, but definitely have experience with spilling my guts in previously unprecedented ways in one-on-one situations. I experienced it in personal relationships, and more recently in therapy. It's always cathartic for me to do this, very definitely helps being in a better place mentally, and can also create powerful bonds with the other person. Being transparent like that can be a bit scary and uncomfortable at first, but once it gets rolling, I would not want to do it in any other way, and it can be such a wonderful relief. I'm sure your sponsor has heard some heavy secrets in his life.