I see that in most of these MLC situations the wayward spouse may be narcissistic and it could have been suppressed by the Left behind until a point where we relaxed our support. OR it could be at the point we relax our support, the wayward spouse meets a strong narcissist. In my experience my MIL was a Narcissist and damaged my wife at a very young age. The traits I had described to me by my wife regarding her mother are now in evidence with my wife. The other day (less than ten days ago) my daughters were discussing an incident I did not know about regarding them and their mother when they were young girls. It was an exact replay of an incident my wife described with her mother when she was teenage (at the same age). I was amazed.
In MLC the person has low self esteem, with contact with a strong narcissist this low self esteem will immediately be detected as a willing host. He (Narcissist) will feed the insecurity and boost the confidence and off they go on the merry go round of an affair. It will be reciprocated as 'poor you, too'.
As Melody Chase describes in her videos about Narcissism on utube, there is always a narcissist in the mix here with MLC and affairs. But as described in this thread, they boost themselves as valuable achievers, but in fact this is all a lie and they have achieved nothing and are desperate to cover it up and have behaviour that says 'look at me, aren't I having a good time'. But inside they are frightened, insecure and suffering. We protected them for a long time. This is a falling glass we cannot catch. We have to watch it fall.
Life is good, once you understand.
We make our own happiness and everyone likes to be with happy people.
One man's junk is another's treasure and life goes on. Make yourself into a happy treasure. :-)