I think if Mark wasn't so set on Leyton, Jeyton would have been together forever. Mark just gave everyone false hope when putting Peyton with Jake. She was always so happy with him, they just went perfectly together. But Mark had to have an LP ending, which I think is pretty screwed up.
I really like J/P but I think that Peyton's feelings for Lucas would have come out either way. I think that's the point Mark was trying to make for them. GO LEYTON.