First off, you are not going to build your self esteem by meeting women or having a one night stand. I think you know that now...
If you want to even attempt to rebuild this M, that behavior, needs to stop. All you are doing right now is acting your way further down the path towards divorce.
I can't say I think your W is MLC or not, although there are some hallmarks.
If the OM is still in the picture, then all you can be to her right now is a friend.
Ultimatums, R talks, will get you no where.
Cadet will be along shortly with links that you can read.
This is not a long or easy road.
There are no quick fixes. No cure all suggestions or ideas.
And it isn't for the faint of heart.
Keep posting, keep reading.
Others will be along.
No one here can guarantee you your M back. If you choose to listen and learn, grow and heal, this will not be a journey that you regret.
Are you ready to become unstuck?
"Acceptance doesn't mean resignation. It means understanding that something is what it is and there's got to be a way through it."--Michael J. Fox