The #1 "piecing" mistake that people make is accepting their wayward spouse back TOO EASILY, and without laying out what your dealbreakers are.
Starsky
This is so important!! Unfortunately I didn't know about DB when I was separated in '98 and I made this very mistake. We were separated for a year and when we reconciled and he moved home, we skipped some important steps. I wonder if we would be having the issues we are having today if we hadn't skipped those important steps. My guess is no, but I will never know.
Be sure to respect your own boundaries and expect him to as well.