In your letter you have made it clear that you are finding some difficulty with sex desire and have asked guidance from me to instruct you how to handle this problem of the material body.
First of all I think you should know that such problems are not very unnatural because in the body the conditioned soul is very prone to failure. But also we must remember that such failure will not discourage us from executing the most important mission of our life, to become fully in Krishna Consciousness. So whatever falldown has been, you should be regretful about it, but it is not so serious nor is it a permanent disqualification. But you must try to check yourself from such artificial things and take full shelter of the Lotus Feet of Krishna. I think that for such checking marriage is the only solution. It is understood that everyone has some nasty habits but by sticking to Krishna Consciousness, chanting our required rounds loudly, and tending the deities, these items will surely save you.
Letter to Upendra, 9 December, 1968