Why is it that the Talmid Chacham has such a "yatzer" to have relations by day?
See Succah 52a at the bottom where the Gemoro relates a story about a great Amorah who said about himself what he wouldn't be able to hold him back from sinning immorally even though a standard person did indeed hold himself back. The Gemoro explains that
Kol HaGadol MeChaveri Yitzro Gadol HeyMenu - One who is greater then his friend has a bigger Yetzer Hora then him.
Therefore, it is easy to understand why a Talmid Chacham in particular should have a yetzer by day!
