Sex is not just for having kids but also for recreation, or more importantly, intimacy between a husband and wife.
Juli Slattery writes that sex in marriage is like LEGOs (which is in line with the series theme): “Culture may have given you a picture on a box—one of bliss, exquisite pleasure and oneness. Perhaps you have been surprised, even disappointed, to find that sex isn’t the ready-made gift you were anticipating. It takes a lot of effort—and a bit of creativity—to make it work” (Juli Slattery, “Sex Is a Creative Process,” Focus on the Family, accessed December 12, 2017).
Sex is to be enjoyed and is a form of connecting with each other. Unfortunately, the world presents sex as something illicit and shallow but God wired humans to have sex and blessed it as a legitimate way for two to become one.