In my previous post, I copied and pasted the purport to SB 3.30.28. There Prabhupada defines and reveals his mood on the concept of illegal and illicit sex. Please see that post if you dont understand what I am saying.
I would like to add some more of my thoughts from this purport. Here is the purport again.
Materialistic life is based on sex life. The existence of all the materialistic people, who are undergoing severe tribulation in the struggle for existence, is based on sex. Therefore, in the Vedic civilization sex life is allowed only in a restricted way; it is for the married couple AND ONLY for begetting children. But when sex life is indulged in for sense gratification illegally and illicitly, both the man and the woman await severe punishment in this world or after death. In this world also they are punished by virulent diseases like syphilis and gonorrhea, and in the next life, as we see in this passage of Śrīmad-Bhāgavatam, they are put into different kinds of hellish conditions to suffer. In Bhagavad-gītā, First Chapter, illicit sex life is also very much condemned, and it is said that one who produces children by illicit sex life is sent to hell. It is confirmed here in the Bhāgavatam that such offenders are put into hellish conditions of life in Tāmisra, Andha-tāmisra and Raurava. - SB 3.30.28
If we further read, following illegal and illicit we get further insights into the mood of the author. He says "punished by virulent diseases like syphilis and gonorrhea". This statement is followed after defining illicit and illegal sex. Syphillis and gonorrhea are two types of sexually transmitted diseases (STDs) apart from herpes, chlamydia and AIDS to name a few. STDs occur when a person has sex with multiple partners at mulitple times without restrictions.
The mood of the author is clear on sex in that he does not want us to have sex enough to suffer from STDs. Surely having regulated sex life with the spouse is much better than unrestricted sex with anyone.
I think that sex inside marriage but for gratification is much better than sex with anyone anytime. Even within marriage, if sex is conducted on a regulated fashion is much better than unrestricted sex within marriage. However, if one wants to cultivate pure love for Godhead, that standard, then, is sex within marriage and only for procreation purposes better yet is complete celibacy.
The author clearly starts from a pure standard and continues to immesurable suffering in the form of syphilis and gonorrhea. Not everyone who has sex ends up with syphilis and gonorrhea. Therefore from a Krishna Con standpoint, the mood of a spiritual aspirant should be towards the end of restricted sex to having children eventually leading to celibacy versus the other way. This is the essence I take from this purport.