GA, Breathe. Try to keep your focus on you and your children and the present...not the future. A lot can happen before the future gets here, but it's not in your control, so let it be.
I do understand where you are coming from and it's h@ll to be in limbo and possibly facing a divorce. Acceptance will come, but it's not going to happen any time soon. You have to go through the stages of mourning the loss of your marriage and it will take time to do so.
No one knows what the future holds. He may not remarry, you may find someone who is wonderful to you and your children, or you may opt to remain single. There is always a possibility that he could wake up and want to reconcile, but those are questions and answers that are in the future and the future has not been revealed to you or him at this time.
This journey is not something he chose to do. It's something that happened within him and again, it's not about you or your children. This is a painful, emotional journey for him and one that he can't describe to you except to say he has to do it, even if it's the wrong decision. I know that this isn't helping, but he would have been going on this journey whether he was married to you or to someone else. It's not YOU, it's HIM. There is something broken within him and you didn't break it, therefore, you can't fix it.
I know you are in pain and you are hurting terribly, but you must find a way to work thru that pain and hurt. Your children need you now more than ever. You are the only stable parent that they have right now and they need reassurances that everything will be okay.
GA, I'm very sorry you are having a terrible day today.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
