Beautiful Girl Hunter (Dabide no hoshi: Bishôjo-gari) - 1979

This might be up your alley, but chance is that it isn't.
The whole thing starts of one rainy night with an escaped sex-convict, a happily married couple and some rope. You can sort of figure out the rest of that evening.
The wife ends up pregnant and her husband can never get over the fact that it isn't his child, so he humiliates and tortures her untill the day she 'off's' herself.
The sons grows to be a man unworthy of his 'fathers' love and constantly reminded of his horrible heritage.
Whit a dick like that as your dad, you just have to search for your roots, don't you?
Hooking up with chicks isn't a problem for this rich playboy, so he builds himself a dungeon to store them in.
The rest of the film is filled with torture, murder and mayhem, but also real lust and true love.
Wait a minute, you might say. What ever happened to his biological father?
What? You want me to tell you the whole fuckin' movie?
Just watch it already!

PS. All timid girls aren't as timid as they might look.

Trailer: http://www.youtube.com/watch?v=UU_sNI3JjAo