(cue the sounds of fangirls everywhere shrieking, or more appropriately, baying like wolves)
Robb has it tough. He was forced to take over as head of House Stark following the shocking death of his father. He then went to war in an attempt to win back his hostage sisters and ended up getting himself declared King. Don't you hate it when that happens? All you want to do is kick some Lannister ass and you end up proving yourself SO AWESOME that all the grizzled old soldiers around you start calling you King. Man, if I had a dollar for everytime...
Wait, where was I? Right, Robb Stark. I mean, just look at those curls. I ask you, what man has hair that perfect? I just want to run my fingers in it. And then yank on it really hard, but that part might be just me.
My point is that Robb Stark is very pretty. Sure, he may not be the brightest bulb, but he's got lots of other great qualities. A very developed sense of duty and honor. A brilliant strategic mind, despite his lack of actual battle experience (though we're working on that). And ok, he really screwed the pooch when he married that dull brown haired girl, but he's a young man with certain...urges.
Actually no, I can't defend that decision.
Because Robb gave his word. If you're a lying Lannister lion that might not mean much, but Robb is a STARK. And he gave. his. word. And then went and married the first pretty young thing that wandered into his path. And now I can't shake the feeling that something bad is going to happen....
You know what they say. Winter is coming. And everyone has to pay the piper. Even Kings.