Welcome to surviving.. which I think at times should be named Thriving Through the Big D..
As difficult as this is, you're in an enviable situation. Both parties want the divorce. Him by his actions. You by your boundaries. And congratulations for knowing yourself and what works for you.
Check into an online divorce. It could cost you only several hundred dollars rather than the thousands, tens of thousands or hundreds of thousands in legal fees that some have experienced here. You can both agree on what's reasonable. Be sure to have a lawyer double check your agreement before the final settlement to make sure it's an even distribution or what works for you.
The less time a divorce takes, the lower the likelihood of animosity. In negotiation, the power goes to the one who hears the first offer. Ask him what he wants then go from there. And the legal aspect of divorce comes down to numbers and percentages. Treat it as such.
How do you handle tomorrow?
Take a deep breath. Exercise. Burn off the excess energy and anxiety. Take a hot shower and choose to look your best.
Remind yourself that you don't hold onto someone who doesn't want to be with you, someone who doesn't cherish and treasure what you share.
Just like people agree to be married, feel good about the agreement divorce. C'mon.. getting engaged? Like a little old Italian woman I know would say, "What a dope!", followed by a smack upside the head.
Divorce, like marriage, begins in the mind.
One last thing, this type of emotional chaos puts both parties in a fog. His with his distraction or focus on someone new. You with an overwhelming sense of pain, hope and betrayal. By choosing what is healthy your fog while clear bringing a new perspective about what is most important and best in life.
Be proud of all you've done right, your belief in marriage, hope for a future together. And most of all, knowing what is best for you. A healthy relationship takes two. And a good life, takes one.