When your child is born you have to put them first and quite literally do everything for them. Your time, your energy, and your thoughts are almost completely directed towards your precious child. In return you are your child's entire world. They look up to you and depend on you for security and meaning. By the time they are teens however, the dynamics change drastically. They look up to others, depend on you less, and often are more focused on getting away than being around you. As off-putting and frustrating as this can be, it is quite healthy.
As your child's dependence changes, so must your focus and priorities. Parenting is still important, but many of your lessons have already been taught and most of your lectures have been repeated time and time again. Now your greatest influence is made through modeling, setting boundaries, and showing that you are happy in the life you have chosen to model. This means that putting your marriage and your happiness first becomes more important than your parenting minutiae.