Your H has been around so little, I think that if you emphasize how little things are going to change from their current situation, the kids will deal ok with it.
They may struggle some once the novelty of going to dad's new place wears off, but really - how much will their lives change? He's already been "gone" for so long.
All you can do is be strong, let them see that you can cope and they can count on you, and that you can still have fun adventures as a family even without their dad there.
