What does Proverbs 5:15 mean?

In this verse Solomon compares monogamy to a well of flowing water. He advises his sons, or students, to enjoy the water that flows from his own well. Part of the joy that comes from sex within marriage is knowing that it is pleasure sanctioned and celebrated by God. The confidence of knowing something is moral, and legitimate, and sacred only enhances the happiness it brings.

The delights of marriage are many. God established monogamy when He pointed out that it was not good for man to be alone. He created Eve from one of Adam's ribs and brought her to Adam. When Adam saw Eve, he said, "This at last is bone of my bones and flesh of my flesh; she shall be called Woman, because she was taken out of Man" (Genesis 2:23). The next verse emphasizes the bond that unites husband and wife: "Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh" (Genesis 2:24). If a man holds fast to his wife, he will enjoy the delights of marriage and not stray into an adulterous relationship.