Divorced parents who raise their children separately usually run into some rough patches along the way, especially if the divorce was particularly difficult. It's a tale as old as child custody law itself, where parents who dislike each other or hold grudges from their marriage use their children to punish or reward behavior in each other.
Primarily, this is unfair and destructive to the child. Any parent who excuses this behavior in themselves needs to take a close look at his or her priorities and ask themselves if they truly believe that the child is unaware of this game.
Unless the child is still an infant, they will catch on pretty quickly, and this will become a fundamental part of how they view the world and interact with it. Parents who ignore this danger and use their children as pawns against each other willingly sign their children up for emotional and relational complications later in life. Simply put, this is grade-A bad parenting.
Unfortunately, it is still very common, as many parents who wish they had thought better of it in the moment can tell you, when their children are distant from them later on and possibly repeat the same patterns themselves.
Protecting your time with your child
It is very likely that your child's other parent has different ideas about child rearing, and may constantly fight you in the area. If at all possible, do not let yourself get dragged into this conflict, but rather stand your ground and document any violations of the parenting agreement by the other parent.
If a pattern of poor behavior and parenting interference emerges, it may be time to consider legal action. Violations of parenting time are a serious issue for the court, and if one parent repeatedly or severely violates a parenting agreement, he or she is likely to lose privileges. Even if a parent abides by a custody schedule, talking negatively about the other parent in the presence of the child is also unacceptable and can result in punishment from the court.
Use the strength of the law to your advantage
While few parents raise their children to adulthood while obeying a parenting plan completely, the closer you stick to it, the fewer grounds the other parent has to accuse you of wrongdoing. If the parenting plan simply does not function for one parent or the other, perhaps consider a modification to the plan, but don't override it simply because it is inconvenient.
The law stands to protect parents and children, so make sure that you are using the full strength of the law to keep your rights secure as you raise the child you love. With careful research and a full understanding of the legal tools you have available, you can better protect your own privileges and build a good life for the child you love.