Taken from the website www.ilovetorah.com
Every tzaddik is faced with the most difficult tests. Chazal say that the higher ones level the greater their evil inclination. There is no tzaddik that exists that wasn't tempted and didn't face sin head to head. We think that because they are righteous they were never normal human beings just like us facing the simple temptations we do. Yosef HaTzaddik covered his face and ran away from Potifar's wife. Rabbi Abraham Abulafia was brave enough in his sefer, Chayay Olam Habah, to admit that he defiled his body from the wasteful admission of seed. He says that for fifteen years, the Satan was at my right hand to mislead me." Also he said that the numerical value of Satan, 359, is the same as that of Zera Lavan, white seed, which is in reference to semen. This goes to show you one of the main goals of the Satan, and that is sexual desire.
Rebbe Nachman says that sexual desire is the great test a man faces in this world. (Rabbi Nachman's Wisdom 115) The Rebbe said that he was able to overcome this desire but he had to cry out to Hashem again and again. The temptations were very real for him but he later said, "A man with even the smallest amount of real intelligence, will not find this a temptation at all." The Satan wanted so much for him to slip on this desire that he was willing to let the Rebbe overcome every other desire if only he would slip up on this once. The Rebbe did the opposite though, and said he would ignore his other desires and not work to control them at all, but the sexual desire he would completely eradicate (Shevachay Haran 16). As a young man, even amidst the fire burning inside him, he overcame this desire completely. He later said, "I do not have any feeling of desire at all. Men and women are all the same to me." When he came in contact with a woman, he didn't even have an extraneous thought. (ibid)