Why marry? Because you want a nice (if somewhat foolish) husband who will probably let you have something on the side if you will permit him the same luxury.
Why f***? Because you’re a gay man. (Also, he’s certainly easy on the eyes; he has the Ser Loras seal of approval.)
Why kill? Because you're a mysterious magical shadow born of a foreign sorceress.
Why marry? Because he’s a king, which comes with its perks. And while he’ll almost certainly not be loyal to you, chances are if you’re not a venomous hag like Cersei Lannister then he won’t be terrible to you or your children.
Why f***? Because if you’re a woman in Westeros, he’s probably already gotten to you anyway. (Besides, he’s probably picked up a few tricks in his bedroom/brothel adventures.)
Why kill? Because you’re a wild boar.
Why marry? Because there’s something to be said for stability and security. Stannis is about as stable and secure (also: boring) as they come.
Why f***? Because of these three options, you just want to pick the one that would be over with the fastest.
Why kill? Because he’s a pompous, stubborn jackass.
Cedar: Marry Renly, F*** Stannis, Kill Robert
Erin: Marry Renly, F*** Stannis, Kill Robert
Jamie: Marry Renly, F*** Stannis, Kill Robert