The way I see it, Robb really loved his father and looked up to him. I am sure that he modeled himself after his father, no matter if it came to personality, leadership or combat.
Now, jumping into bed with Jeyne was probably what made Robb lose the war and his life. My question is: Why wouldn't he? Surely his father had never said anything about his responsibility to his wife, since Ned himself did the naughty while at war. Even if R+L is true and Eddard was faithful, Robb did not know that. Ned just do not strike me as the type to preach something he himself was unable to do, and too bad of a liar to talk about that stuff if Jon really isn't his kid.
People seem to blame Cat, Robb and even Sansa for what happened to Robb, but for once I really think it was Ned's fault. Robb didn't know any better, and his dad should have made it clear that marriage alliances always come first, love second.