All situations are different, so I respect your right to handle it as you see fit.
As for OP, my counselor once said to me that only my wife made a vow to me. Of course, OM knew what he was doing. What I see going on around here is to make the OP the bogeyman and relive the wayward spouse of guilt because of their MLC. My wife was being a slimeball when she went off with a known philanderer.
The real point to the whole discussion however is if one lets something or someone bother them, they will every time. And who does it hurt. Not them. We can all make a decision not to let someone or something bother us.