Some are not strong enough to do the work or leave without someone to go with.It's a weakness in them.
That was my X to the T. He couldn't face his own faultsand weaknesses, so he went looking for someone to be "new" with. I honestly believe he never would have left if he din't have her to go to.
"You can't stop the waves, but you can learn to surf." Jon Kabat-Zinn