Welcome to the club that nobody wanted to join. You will find strength and healing here.
Yes, your W is dating another man.
First things first, read all of the links that Job provided and pick up a copy of Divorce Remedy.
Social media will cause nothing but obsession and grief for you. Stay completely off of social media for the foreseeable future.
No contact, unless it’s about your kids, is going to be your best bet and will help expedite the healing process. Right now you might feel like your life is over, you will never be happy again, and that no one will ever love you like your W used to. With time, you will come to find your self worth again and realize that you already have the recipe for happiness locked deep within yourself. It will take time for you to discover that, but you will.
You’re going to survive this, and even come out the other side a better version of yourself, with or without your W.