Booyhoo,
Really sorry to hear that your relationship has ended, but good to hear that you feel better today.
I am 5 years on from this scenario, and want to assure you that it can work for your DC's.
EXP and I were fairly amicable when we split and worked out a fair shared parenting routine that we are both comfortable with, obviously, we would both like more time, but understanding that fact helped us to make the right decisions rather than selfish nes and as a result our DD is amazingly happy, and loves both her families and homes equally.
We alternate Christmas and Boxing day (so she in effect actually just gets 2 christmas days - father christmas vists both nights) and alternate new years eve.
I know all of this will be a little way off for you, but just to reassure you that it can happen amicably, and can work out for everyone, most importantly for the children.
Good luck with the CM-ing, I hear its hard work!!!