The eternal self is that which lies outside of the consciousness of the body, the mind and it’s collective consciousness (awareness, memories etc.) of things and events, the intelligence and so forth. The eternal self is that which has never not existed and that which continues to exists after the body is annihilated. Though desires may follow one into the next life, the eternal self is that which supports this karma, and is also separate from it. To become one again with that pure self, one must give up all association and identification with those things that one fears, holds dear, or simply desires. For men, this may mean letting go of one’s strong attraction for the opposite sex. In this verse Krishna is instructing Uddhava, a man, and so he is using this example. When Krishna instructs women, He instructs them that they too must let go of all attachment for family, home etc. and reestablish one’s eternal relationship with the Divine. When someone is ready, it is time to find a solitary place, and concentrate only upon God with rapt attention.
“Attraction and repulsion for sense objects are felt by embodied beings, but one should not fall under the control of senses and sense objects because they are stumbling blocks on the path of self-realization.” Bg. 3.34
“The Personality of Godhead answered: That yoga system which relates to the Lord and the individual soul, which is meant for the ultimate benefit of the living entity, and which causes detachment from all happiness and distress in the material world, is the highest yoga system.” SB 3.25.12
“When one is completely cleansed of the impurities of lust and greed produced from the false identification of the body as “I” and bodily possessions as “mine,” one’s mind becomes purified. In that pure state he transcends the stage of material happiness and distress.” SB 3.25.16
“In that position of self-realization, by practice of knowledge and renunciation in devotional service, one sees everything in the right perspective; he becomes indifferent to material existence, and the material influence acts less powerfully upon him.” SB 3.25.18
“Every learned man knows very well that attachment for the material is the greatest entanglement of the spirit soul. But that same attachment, when applied to self-realized devotees, opens the door of liberation.” SB 3.25.20
“Now for the matters you wrote about: “It is good for a man not to have sexual relations with a woman.” 1 Corinthians 7:1