"Something" keeps them coming back to the LBS; part of it is the longstanding history they have with the LBS; but yet, I believe it runs deeper within the spiritual level....the LBS is the stanchion, the strength, the lighthouse, the draw for the MLC'er.....and it keeps them coming back to "check" on where they are..to see if they are in the same place they left them.
Although their feelings are buried deeply within, the MLC'er really does STILL have feelings for the LBS; although guilt, shame and a sense of being "broken" within are at the forefront.
Many MLC'ers KNOW deep in their heart that OW/OM was never meant to last, but they are looking for a temporary band aid for the pain, as well as working out some of their issues or "replaying" times of their lives they hadn't finished right to begin with.
And when these types of issues are completed, they process into the awakening from this part of their lives; and they come to several realizations; one of which is they find they don't love the OW/OM at all, they still love the LBS...and that is even after all the fighting they do within to break that connection while within the affair; it remains unbroken, and unresolved within them.
That seems to be why after some years, SOME "wake up" and realize what they have done, trying to come back; but by that time too much water has gone underneath the bridge, and may be the LBS has moved on, having remarried, or moved on to a place where they don't love the MLC'er anymore.
It's weird; in their hearts, they don't see themselves as married to the LBS, but yet they keep coming back, because something deep within them keeps them doing this.
There IS a link between the MLC'er and LBS, as evidenced from the going back and forth between OW/OP and the LBS; OR if there's nothing like that going on, they still pop up at times; even after moving out.
It DOES also evidence wanting to control what happens with the LBS, much like an obsession..but is part of the tunnel and childlike behavior; thinking like a teenager.....always needing an "anchor" to go back to, yet wanting to be on their own.
Analyzing this behavior is fruitless at best; that's why it's so important to let go and let God work on them, all the while, focusing on yourselves. If you try and make sense out of everything they do, it will drive you crazy.
Some things just won't make ANY sense, no matter how hard you examine them....and, assuming they make it through, it will mostly be forgotten as time, acceptance, forgiveness, healing and rebuilding the marriage puts them in the place they need to be....in the past where they belong.
Only HE knows what's in store for the future; and some things you may never know the answers to, only that it is what it is, and most things are attributed to the tunnel, and the many aspects within the MLC'er is facing.
Anyway, that's MY take on it.