"The most important thing a father can do for his children is to love their mother."
This should go without saying, but the reverse of this is true as well. If you are blessed to have a two parent household, spend at least as much time cultivating that relationship as you do working on your parenting. To a child, there is nothing more comforting than knowing that all is well between mom and dad, so don’t allow your children and your concern for them to dominate your marital relationship.
If you are divorced and find yourself co-parenting, this quote is still just as true. By treating your child’s other parent (regardless of how you feel about them) with respect and love, you are giving your child a true gift. As difficult as it may be, work your hardest to keep that relationship positive so that your child doesn’t have to shoulder your burden as well as their own.