Maybe it would help if you tried to think about the children in a new way.
Let's say your H did come home but wasn't all in. Didn't you say he bought a book about how to stay married for the sake of the children? If your H moved home and did not work on his issues along with the issues the two of you have nothing would change. And your children would grow up witness to a loveless and strained marriage. Young children get it. I know my sister and I did!
If your H did come home and things did not change your children will know. As they grow older and become more social they will begin to see how other healthy marriages work and quickly realize the marriage they see at home is not healthy. It does not matter if you don't argue in front of the children or not. You had said that you lived in a celibate marriage void of physical affection. Children will see their parents don't hug and kiss and have physical touch. Children will develop the same bad habits you and your H have.
I bet your children do miss your H when they are with you and I bet they miss you when they are with your H. Obviously that is the very sad part of divorce and certainly something that will need long term emotional care and handling.
My parents never argued in front of us per say (us = my sister and I) but the vibe was always very, very off. It was all a farce and we knew it from a very early age. My mom tried like hell and went to marriage counseling along for decades. Eventually my sister and I lost lots of respect for my mom for not only staying in that situation but also for the continued exposure we had to it. The quiet stress and oddness of it all was a terrible burden for my sister and I to carry.
You already have and will continue to create a great family for your children. Your H is going to do what he is going to do but it seems he is also trying to create a family for the children. And no matter what happens between you and your H the four of you will always be a family in some capacity.
So, yes, the divorce will have an impact on your children and it will take careful work when dealing with the impact. But it would also have an impact for your children to grow up watching their parents in a very unhealthy and unloving marriage.
In a way you remind me of my mom. When my sister and I were young my father used to work very early in the morning and get home by 2pm. He always came home in a "mood" and my mom would try and act as the barrier as we tip toed around him. I am sure it was exhausting for her and it was terrible for my sister and me. And you said you used to have to do the same thing.
Sure, you made mistakes in the marriage... WHO HASN'T? Even at their young age though you had the terrible burden of shielding your children from your H's very bad behavior (sleep issues he did not take care of, mood swings, becoming angry when things didn't go how he planned). Do you really want a life of dealing with *that* with a big part of your time dedicated to being the barrier as to not to further upset your H?
