A Gift of Teshuva
We all know from the Rambam that complete teshuva is when you are in the exact same situation with the same temptation, yet you overcome the temptation. Sometimes, it's hard for me to imagine being in the exact same situation with the same level of lust. The temptations of 20 years ago are not relevant to me today, and I'm certainly not looking to deliberately recreate the temptation, so this could be disheartening.
I think it's the Ohr Hachaim Hakodosh who says that Shabbos supplies this factor of recreating the same environment:
Odom Harishon was expelled from Gan Eden so it was not possible for him to be put in the same matzav, so he did teshuva on Shabbos - the very first Shabbos, after he was created on Rosh Hashana, was the first Shabbos Shuva.
May we all be zoche to the gift of teshuva.