H.M.
I have 3 kids, and when we divorced the kids were 1,3 & 7. We were separated before that and my youngest didn't go for an overnighter until I was done nursing. My kids are now 5, 7 & 11 - we've been doing the same schedule with flexibility since then. Their dad has them every other weekend, and then every other Thursday on his off weekends. He also rotates Weds. nights to have some one on one time with each of the kids.
It's not easy, hang in there!