In addition, I see a fair number of people who DO save their M's, yet it's clear (and often their return a few years later proves this) that they didn't finish working on themselves. And the problem is always a combination of not having detached sufficiently AND not having established adequate boundaries; they end up "settling" to get their partners back (or in new relationships) and lack the confidence to enforce clear boundaries.
Agreed again. That's why Piecing is the hardest part. Without real change (almost always by BOTH parties), and NEW, HEALTHIER boundaries put in place, the recidivism rate for infidelity is, sadly, extremely high.