One very, very helpful frame was said to me by our couples therapist:
"There are some conversations that couples, even those who've been married for 20, 30, or 50 yrs, never have".
It was a "DUH" moment for me - I assumed that my wife and I agreed that our marriage would be monogamous - I'm guessing that this is true for so many of us and that's part of what blows ours minds when an affair happens...it's like, "WAIT...I thought we had an agreement".
I initiated the conversation yesterday...I was surprised at first that my wife had difficulty hooking on to what I was asking her - then realized that I had to ask more directly. So, I said "I am hurting so badly from your love affair - I carry my hurt around constantly and every trigger breaks my heart...I need to know that our marriage is based on monogamy - are you in agreement with this?".
Having led with my hurt, my wife could hear me - whatever else had gone on in her head, she is clear that she does not want to hurt me and is sorry for the hurt she has brought...and, so, she gave me assurance that she was committed to a monogamous marriage, and , in a way that I believe to be true.
I think that leading with my hurt worked because it did not trigger blame in her...and, the proof is that my wife suggested that we set aside time each week to talk about her affair, my hurts, my triggers...and, believe me, this is a BIG step.