SB 9.19.11
sambaddha-vrsanah so ’pi
hy ajaya kupa-labdhaya
kalam bahu-titham bhadre
kamair nadyapi tusyati
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
My dear wife, when the he-goat had his testicles restored, he enjoyed the she-goat he had gotten from the well, but although he continued to enjoy for many, many years, even now he has not been fully satisfied.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When one is bound by affection for one’s wife, one is attached to sexual desires that are very difficult to overcome. Therefore, according to Vedic civilization, one must voluntarily leave his so-called home and go to the forest. Pañcasordhvam vanam vrajet. Human life is meant for such tapasya, or austerity. By the austerity of voluntarily stopping sex life at home and going to the forest to engage in spiritual activities in the association of devotees, one achieves the actual purpose of human life.