My H and I went to a Retro weekend. It is all about communicating and being able to be your most authentic self in front of your spouse.
To me working on your M means trying to see where you are off track and working to get there. The difference is for those of us not wanting a D, doing the "work" is more appealing. Those who have mentally checked out or who have another person affirming them (OM/OW) may have no interest in anything that looks or sounds like work. This is a tough one to answer for me...