So far maithuna [sex life] is concerned, it is completely rejected. Bhaktim param bhagavati pratilabhya apahinoti kamam [Cc. Antya 5.48]. This is Vaisnava. Vaisnava means as he makes progress in devotional service, these material lusty desires become vanquished: No more. Finished. Bhaktih paresanubhavo viraktir anya… [SB 11.2.42]. This is the sign. Yad-avadhi mama cetah krsna-padaravinde nava-nava-rasa-dhamani…, tad-avadhi bata nari-sangame smaryamane bhavati mukha-vikarah [Sri Yamunacarya]. This is Vaisnava. When one will spit of sex enjoyment, that means he has attained the Vaisnava stage. Otherwise not yet. That is the test. Yad-avadhi mama cetah krsna-padaravinde nava-nava-rasa-dhamany udyatam rantum asit, tad-avadhi bata nari-sangame. Because nari-sangame, sex with nari, that is the highest pleasure of this material world. Yan maithunadi-grhamedhi-sukham hi tuccham [SB 7.9.45]. Very abominable happiness, maithunadi. It is kanduyanena karayor iva duhkha-duhkham. It is entailed with so many sufferings. Either illicit or legal, there is suffering.

From Srila Prabhupada’s lecture on Srimad-Bhagavatam 1.7.22 — September 18, 1976, Vrndavana