I'm so sorry... your pain is palpable.
I wish I had an answer for you... Facetiming every day may not be the optimal substitute but it's something. Do the terms of your divorce allow that?
How often do you get to have your kids with you overnight?
You're grieving right now and need someone to rely on to share your feelings. Do you have a support network where you feel safe and not so alone? Friends? A counsellor? A doctor?
Again, I'm so sorry for your pain...