We feel for you - we really do.
But what's important- as you say- right now is the kids. You (both) are going to be giving them their first lesson in relationships and conflict resolution. They will carry that forward into their own lives !
People get 'married' for various reasons. Often it seems the wrong ones - or prematurely. Then some (not implying you guys) feel that children will 'fix' the gap that everyone senses. Bring you closer together. Doesn't work.
The hope now is that you BOTH realize the position you are in, in relation to the children. Ideally the children learn from this that 'love' has many forms and is subject to change over time. As people learn more about each other and grow in their own lives - it can happen that they grow apart. Of course the loving way to acknowledge and process this is with respect. It's a love of a different form - a desire for the other person to be able to move their life in the direction that's best for them - even if it means moving in opposite directions. And there's no inherent conflict in that. But the kids need that broken down in terms THEY can understand and it's sooooo important that they realize that it doesn't impact the love you both have for them. I know she DOES love them. I think it's literally impossible for a mother not to love her blood bonded offspring. But in her confusion and self absorption (we only have your side of the story) they are being pushed to the side. Sad. That WILL change ! If you can make space for that and try to explain to the kids about her confusion & distraction, and offer them the assurance that she still loves them and will "recover" in a little while - it will help a lot. Like an illness.
But it's "OK" for lovers to grow apart and need to go off in their own direction. In some cases it's absolutely the only sensible option. But it CAN be done with love & kindness and support.
Therin lies the lesson........