The Heavenly Bodies series of three short fics by Dare has Spike wanting to sleep with Buffy to get back at Angelus. Each fic is complete even though the overall scenario doesn't get closure.
Heavenly Bodies series by Dare
There are a couple I can think of that are S2 revenge sex based so a degree of being hung up on Dru or at least jealous of her/Angelus but I'm not sure how much, I haven't read either in a while...
Wheels on Fire by greyangel has that revenge sex angle too. I don't think it is online but I have a copy in Word if you pm me your email address.
Meant To Be by nataliav
Set at the beginning of "Lie to Me". Buffy sees Angel with Drusilla, and so does Spike. What should have been a night of comfort serves to release desires and sets Spike and Buffy on the road to true love.