Maybe soon someone will kindly put me into a padded room and shoot me full of drugs.
Ha! I've had this thought several times myself, and was only half not-serious.
I don't know you're entire sitch, but from this post, I would advise taking things one step at a time, and take stock of how you feel along the way. There is no rush on any of this stuff.
I know it's hard, but what else could you be doing with your time besides worrying whether your W is 'actually' cheating or not?
IMO, if you end up D, there will be plenty of time to explore other fish in the sea, from hopefully a more grounded place. This time is for YOU, to get yourself to a good place. A place where whether or not your M ends, you will be emotionally ready, healthy and happy enough to build a good R. And if you're happy, your kids will likely be, too.
It is in the shelter of each other that people live.--Irish proverb
