The father's heart for your sexuality is joy. Maybe you need to read that again. God created sex to be enjoyed by a husband and wife. Sex is not just for procreation or for satisfying a biological drive. God desires that the husband and wife be "intoxicated" with the love they share for one another. In other words, heterosexual marriage is the only context where the goodness and power of sex can come together to create a life-giving, joy-filled, and soul-satisfying sexual relationship. This is where the two become one in a way that glorifies God (Genesis 2:24; Matthew 19:5; Mark 10:8; 1 Corinthians 6:12-20; Ephesians 5:31).
The father here in these verses of Proverbs is imparting perspective to the generations that follow him. In particular, he is continuing his teaching on the dangers of adultery and forbidden sexual relationships. He is telling his sons (all of his posterity) to listen to the perspective of an older man. They will lose so much life if they look for sexual fulfillment outside of marriage. Whatever pleasure they think they might gain will ultimately end in regret.