When I first met my better half, she actually hated my guts. I knew this and would go out of my way to do things that I knew would aggravate her, then would snicker to myself when she stared screaming about it.
In all rights the both of us are about as opposite as day is from night. I guess that this proves the old saying that opposites actually do attract.
As far as "fornication" goes, I've found that one of the best things that keep us going.. is to avoid routines.
work
come home
got to bed and have sex
wake up next morning
go to work
come home
ect..ect..ect!!
One thing that I really love doing to avoid this, is having "surprise sex", or trying (note: T-R-Y-I-N-G) to get it from her when she either isnt prepared for it, or is not expecting it. Sometimes it works, sometimes it doesn't!
I've known her long enough to know when (and when not) to make any attempts, simply be studying her body language.
May sound crazy to most people, but so far it's kept us together.