Sex serves as the natural attraction between man and woman, and when they are married, their relationship becomes more involved. Due to the entangling relationship between man and woman, there is a sense of illusion whereby one thinks, “This man is my husband,” or “This woman is my wife.” This is called hrdaya-granthi, “the hard knot in the heart.” This knot is very difficult to undo, even though a man and woman separate either for the principles of varnasrama or simply to get a divorce. In any case, the man always thinks of the woman, and the woman always thinks of the man. Thus a person becomes materially attached to family, property, and children, although all of these are temporary. The possessor, unfortunately, identifies with his property and wealth.
Sometimes, even after renunciation, one becomes attached to a temple or to the few things that constitute the property of a sannyasi, but such attachment is not as strong as a family attachment. The attachment to the family is the strongest illusion. In the Satyasamhita, it is stated:
brahmadya yajnavalkadya mucyante stri-sahayinah
bodhyante kecanaitesam visesam ca vido viduh
Sometimes it is found among exalted personalities like Lord Brahma that the wife and children are not a cause of bondage. On the contrary, the wife actually helps further spiritual life and liberation. Nonetheless, most people are bound by the knots of the marital relationship, and consequently, they forget their relationship with Krishna.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Fifth Canto, Chapter 05 – Text 08