It's not hopeless. My H and I were separated for five months and even after he was physically back in the home, it took years of piecing. Use the time now to work on you. Read the books, do what the coach tells you to do. Get involved in some activites that you enjoy and will take your mind off things for awhile. Like most women, you've probably spent too much time taking care of everyone else and no time for yourself. I'm giving you permission right now to do things just for you.
I'm sorry to tell you that you will probably discover an affair that has been taking place for awhile. My H had been carrying on an EA with a coworker but came to me crying about how much he loved me but needed space. The reason he needed space was to lessen his guilt about taking the affair to the next level.
But no matter what the future holds, you are in the right place. You will get solid, practical advice here. We won't lie to you or tell you everything will be ok when it won't. But I can tell you that YOU will be ok. You will find strength you didn't know you had.
First practical step to take, protect yourself financially. Talk with a lawyer about child support. If he needs space, fine. Let him see how long he can last at his mom's, but he can't abandon his financial responsibilities. That will also give him a dose of reality to deal with.