Anybody in an LDR?

My husband is in SC and I'm currently in KY. I have two daughters with my ex husband (who is NOT working with us at all!). Hubby can't move up here because he's military, but I don't know if I can move to be with him, without losing custody of my other two. We have 50/50. He's only going to be there until September 2016, but that'll be after this baby is here and he's going to miss most everything.