Please place no stock in the fact your W went to the MBR to speak to you. Don't place stock in the fact she hasn't filed for a divorce, either. Your MR is in serious trouble, and it cannot be fixed the way most H's want to fix relationship problems. Buying roses, sweet talking her, and having sex......won't patch it. If you'll stay with us, you will get support and tell what you can do.
Can you tell us about her growing up years? Did she suffer any type of abuse as a child, or experience some traumatic event that was life changing for her?
Has there ever been inappropriate contact with the opposite sex from either of you in the past?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!