Yes my advice is that the LBSers MUST move on. BUT Moving on does not mean we slam and lock the door behind us, but it does mean we stop looking behind us to see if our WAS has noticed, or turned, or is GAL and all the obsessing that goes with guesswork re a WAS....so tiring and wasteful and it very much hinders our own path and growth....
Constantly Looking over your shoulder is no way to swim to the other shore.
Just get to the other shore, to the place where their actions/feelings/plans are NOT our priority or focus.