Sometimes rivalry can develop between parents over their children's attention and love. If Dad wants his daughter to spend Saturday afternoon fishing with him but Mom wants her to go shopping with her, they may struggle to get their way, putting the child in an unenviable position, right in the middle of the conflict.
The two of you need to find ways to cooperate, not compete, with each other. That doesn't mean you have to agree on everything; but it does mean that you are committed to working together toward a more harmonious relationship and family life, and you are not going to let differences undermine your common goals. Each of you needs to demonstrate some flexibility.
As you form ground rules for the family, identify the areas in which each parent excels. That parent should then exert leadership in the areas of his or her strength, so the decision-making responsibilities are divided within the family.