"I have another question on this matter", continued Yerachmiel; "even if I am able to internalize that all other women in the world are not relevant to me at all and my wife is the only one permitted to me, how do I erase all the memories from the many sexual experiences that I unfortunately had in the past, which pop up in my mind morning and night without invitation, particularly in the least expected times? It could happen in middle of davening, or while I'm learning with my Chavrusah. Even yesterday, when I went out with my Kallah to a restaurant, suddenly in middle of our conversation, without any connection to anything, I found myself going over in my imagination one of the sexual experiences I had; and as much as I tried to get rid of these thoughts, they only got stronger. What should I do if such thoughts come into my head while I'm with my wife?"
I smiled to him. "Another wonderful question. Again this shows how seriously you are taking the responsibility of the new home you are about to build".
"One of the central factors of a person's personality is his memory, without it we couldn't function at all. But let me ask you a question. When these memories enter your head, in what context do they come up?"
"What does that mean, in what context? In a sexual context of course!"
"Obviously, Yerachmiel", I answered. "Let me rephrase the question; are these memories pleasant to you?"
"Unfortunately yes", answered Yerachmiel flustered, "they remind me of all the pleasurable experiences I had in the past, even though now I regret them very much".
"And when these pleasant sexual thoughts come up in your mind, do the thoughts of disillusionment, regret and sadness that these experiences caused you, come up in parallel as well?"
"Totally not", answered Yerachmiel pointedly, "only the memories of the sexual experience itself come up in my head".
"Did you ever ask yourself why? After all, we both know how much pain and suffering these deeds caused you. So why don't these feelings come up as well, together with the pleasant sexual memories? The answer is, that the human mind distinguishes between pleasant memories - which it chooses to keep, and unpleasant memories - which it chooses to push away and forget. Forgetfulness is a big gift, it's a divine kindness that Hashem does with us so that life can continue even after we underwent difficult experiences or loss. If we remembered everything, we wouldn't be able to function at all; we would be sad and depressed the whole time."
"So for me, forgetting is a double edged sword!", called out Yerachmiel.
"Not necessarily", I replied. "As long as your mind continues to catalog the sexual experiences that you had as pleasant, they will continue to pop up in your mind again and again. The only way to prevent this is to change the status of these memories, in other words; to turn the sexual memories from pleasant memories - which the mind wants to keep, to difficult and bitter memories - which the mind will try to forget.
"But how do I do this?" asked Yerachmiel.
"There's an effective and simple way", I replied. "From now on, accustom yourself that whenever sexual memories pop up in your mind, instead of trying to forget them - like you've been doing until now without much luck - try and remind yourself of all the suffering and pain that they caused you as well. This way, slowly but surely these experiences will be transformed from pleasurable memories which the mind wants to save, to difficult experiences that the mind will do everything it can to push them away."
"I am speechless" said Yerachmiel. "How does the Rav know all this?"
"On my own I wouldn't know anything", I answered. "But Chazal taught us: 'Thoughts of aveiros (sins) are worse than the aveiros' (Yuma 29a). But this is hard to understand. Is thinking of a sin truly worse than someone who does the sin? Think about it for a second; who is worse, one who does the sin in practice, or one who thought about doing it but in the end overcomes his evil impulse and doesn't do it?"
"Of course, the one who sins in practice!", said Yerachmiel.
"But Chazal are teaching us, that thoughts of sin do more damage to a person than the sin itself. Perhaps this can be understood in the context of what we just discussed. Chazal, in their great wisdom, understood that in the case of sins we did in practice, we can feel a strong regret afterwards and do Teshuvah on them, and these experiences will be ingrained in our minds as painful experiences that we would prefer to forget. But this is not the case with sexual fantasies, which - even if we succeed in overcoming our desires and not sinning - the fantasies themselves become ingrained in our minds as things we would have liked to do, and memories of these pleasurable fantasies can be ingrained in the mind for a much longer time."
I saw that Yerachmiel was trying to digest what I had just told him. Finally he said, "I have one more question, but I am embarrassed to ask it to the Rosh yeshiva".
"I suggest we finish up for now", I said. "Mincha is in a few minutes and it would be a shame to talk under pressure. How about you write down the question and give it to me tonight, after Maariv? This way you'll feel less uncomfortable, and be'ezrat Hashem tomorrow afternoon we'll work it out together".
Yerachmiel accepted the idea happily and went his way.