The worst part of divorce has got to be "sharing" your child. Some people are under the false belief that once you divorce you are free of the problems you and your former spouse shared. Not so if you have children together. You are forever tied to that person through the child you produced as a married couple.
Holidays are difficult as you try to "split" time with your ex spouse. This can be especially stressful for the child. Do everything you can to minimize this stress. Holidays are supposed to be fun and relaxing. Even if it isn't for you, it should be for the children involved.
Refrain from pouting or making derogatory remarks about the other parent in the presence of the children. It doesn't serve any constructive purpose and makes the children feel bad.
Instead of fretting over the time you DON'T have with your child, make the most out of the time you DO. Talk with them, hold them, do activities with them and take pictures of them. Most of all...love them.