Oh Harvey, I am so sorry. That was heartbreaking to read. It seemed that you both handled it as well as you could. When we told the girls H was MO we all sat in D9's room holding each other. D12 asked "how long" repeatedly and H said "I don't know?". D9 didn't say anything. Just cried. H took D12 up to her room to get ready for bed and D9 looked at me and said "how long?". I never want to see my children in that pain again. I know H doesn't want to put them through that again. It was the hardest night of both of our lives. He cried for days (I saw it in his eyes).
A few months later and I was doing the school run. That morning the universe seemed to be against us, missing shoes, traffic, everything. We dropped D9 off and I was taking D12 round to her school. She said something (I can't even remember what it was) and I screamed "Daddy has left and I am doing the best I can". Before I knew it tears were streaming down my face. She looked straight ahead and pretended not to see. It was wrong to put that on a 12 year old.
My children have never mentioned it again. They never talk of him other than to ask when they are going to see him. We have tried to make it seem normal for them. And now, apart from the random comment, sleeping in our beds again, and D12's tummy aches, it is normal for them.
Keep an eye out. They will not tell you they are hurting but they will be. Keep them busy, give them lots of hugs and reassurances. It will hurt like hell when you try and get them excited about being with mummy, or when you ask they how their day was after they come home from seeing her, but it is the right thing to do.