When people were asked to recall the financial sacrifices they'd made for their kids, they also reported being much happier as parents than those who were not asked to recall the financial pain of parenthood.
This could be viewed as simply a rationalization, but the same study found that parents who were first encouraged to idealize parenthood and visualize all the pleasant things involved reported many fewer feelings of negativity about being a parent. Focusing on the positive also minimized the negative.
Rather than lamenting the costs associated with your child's education, try to focus on the many ways in which it will benefit him or her. Say to yourself, "Yes, it costs a lot, but my child is getting a good education, learning to think critically, making friends, and learning to play violin and basketball." Shifting attention from the cons to the pros is, as in any aspect of life, the most productive approach.
Take Time to Yourself, and Your Spouse
As most parents will tell you, leisure time -- doing fun activities by yourself or with your spouse -- is a key to parental happiness. In fact, studies have found that after women became mothers, they enjoyed their leisure time more than before (which is not surprising, since there is much less of it after the baby comes along).
Personal time, either by yourself or with your partner, is an important part of maintaining your sense of self -- and your sanity. Pursue a project you want to do; take a walk, visit a museum, listen to a CD you love. (In the same study, women also rated their moods as less negative toward their relatives after the birth of the child, which could suggest that having a baby makes one a little less hard on family members.)
Spending time with your spouse is also an important tool for getting through parenthood. Though couples' alone time drops off sharply after a baby is born, it tends to climb in the months after -- maybe not to pre-baby levels, but still. And the kind of leisure time couples spent before the baby is born has a lot to do with how well the relationship works after the baby is born. For example, women who spend more time enjoying leisure activities with their husbands before having a child are generally happier in the first year of their child's life. For men, the situation is similar: the fewer leisure activities men do by themselves, the less conflict they experience after the baby is born.
So make sure that you have a night out with your significant other, whether or not you're a parent. If you haven't yet had a child, make the most of your time together, because it will translate to the strength of your relationship postnatally. And if you already have kids, make sure to give yourselves a night off once in a while, since doing so can increase your bond with each other, which will be a benefit to your child as well.