The absolutely worst time in my life was telling the kids. Mine happened about two weeks after the bomb.
From my experience, make a plan.
Write out what your belief is.
Anticipate any and all questions the children will have, especially about birthdays, vacations, where they live.
Work with the counselor together, so you two go in as a united front. This is all about the kids, helping them during a very traumatic time, reassuring them it's not their fault, that you aren't going anywhere, that you will always love them.
Let her take ownership. Don't come to her rescue.
And, if you're both together, you know what's said. And this is a brand new beginning of a very different sort. Very very tough.
Your kids are young enough that they deserve to have both parents reassuring them as a united front.
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A story I heard once..
A recently divorced father took his two distraught children out to the backyard. "Gather all the twigs you can find and bring them here." The kids scampered around depositing some and running to find more as the father built a tight bundle of the twigs.
As the kids rested the father stood before them and started twisting at the bundle. "This is like the love your mother and I had for each other." With much effort bits of wood started to break off as the father talked, the children watching. They saw how hard he had to work as the bundle slowly broke apart.
The father then asked the kids to find sticks, which they did, following the same pattern as before. The father wove the sticks into a tight bundle and started trying to twist and break it as before. No matter how hard he worked, the bundle stayed secure, whole. The father looked to his children and said, "This is the love I have for you."
