Few writers have as large an influence on their chosen medium as Chris Claremont. He shepherded the X-Men from an already canceled book to Marvel's most profitable and prolific franchise. And, in the process, was far more influential than commonly cited works like Watchmen and The Dark Knight Returns. While praising those books for the quality of their story telling, what everyone really wanted was to be the next X-Men (including characters that pre-dated the X-Men). Claremont wrote seminal, brilliant stories and created memorable, beloved characters all of which have stood the test of time.
However as his sixteen year stint writing Marvel's mutants carried on, his weaknesses as a writer became increasingly more apparent. One of his most frustrating traits was his inability to let go of a plotline when it was no longer relevant, logical, or even coherent. As a particularly egregious example, there is the case of Madelyne Pryor, Claremont's original ending for "The Dark Phoenix Saga" was to have Jean Grey stripped of her powers and move to Alaska with Cyclops. However, as the Phoenix had killed billions of people this was deemed not punishment enough. Editorial wanted Jean held on an asteroid and tortured until the end of time. Eventually they split the difference and Jean heroically commits suicide to save the universe.
After Jean's death, Cyclops bummed around for awhile. He dated a boat captain named Lee Forrester. He rejoined the X-Men, left them, and generally just hung out. But Claremont desperately wanted to do his ending to "The Dark Phoenix Saga" even though Jean Grey was, you know, dead at the time. So when visiting his parents in Alaska he meets Madelyne Pryor, a woman who just happens to look exactly like Jean... except without any powers. In less than ten issues the pair is married.
There is nothing about this storyline that isn't deeply weird and warped. Cyclops could just have easily wound up in Alaska with Lee, but she wasn't Jean Grey. Claremont seemed to think it was incredibly romantic, and yet when specifically talking about the storyline states his reference point was Vertigo, a movie about mental illness and obsession. At one point Cyclops outright askes Madelyne if she is Jean, and Madelyne hits him. To Claremont this symbolized, "Because her whole desire was to be deeply loved for herself not to be loved as the evocation of her boyfriend's dead romantic lover and sweetheart." Except that by hitting Cyclops she (and by extension, Claremont) is merely avoiding the question, "how is Madelyne any different than powerless Jean Grey?"
At the end of "The Dark Phoenix Saga" Cyclops went on a long night of the soul. He was growing and changing, by necessity, from the trauma. The introduction of Madelyne throws all that character development out of the window, rendering him a crazy guy so obsessed with his dead highschool girlfriend he marries a woman he barely knows because she looks like him. Which, of course, means quite a lot of trouble when Jean comes back.
When Jean Grey was found alive at the bottom of the ocean, Cyclops abandons his wife and child to run off and be a superhero again. This event has caused a significant portion of X-Men fans to loath him, including Claremont himself (who wasn't writing that particular X-Men book). But the fact is that Claremont had put the character in a narrative bind without any way out. The minute Cyclops married Jean Grey Lite it was inevitable that he'd return to the real thing if she ever came back. Madelyne was literally created to be a placeholder for Jean, and now that Jean was back she served no purpose. There was just no possible in character reason that Cyclops wouldn't leave her immediately.
Claremont used Madelyne as a supporting character in his X-Men title, and eventually she was revealed to be a clone of Jean, given both magical and telepathic powers, turned evil and killed off. Turning Madelyne evil actually gave the character a solid motivation different from Jean Grey, and is the primary reason why she continued to pop up intermittently over all the years since her death.
Cyclops and Jean eventually married, but their marriage was never as happy as other Marvel characters' marriages (Marvel loves a troubled marriage, but normally they are counterbalanced more evenly). They came off as two people who couldn't get over the fact that they dated in highschool, because that's basically what they were. Scott spent the five years Jean was dead with a placeholder and Jean jumped right back in a relationship with him out of inertia. Both of them contemplated straying (Cyclops with Psylocke and Jean with Wolverine). Throughout the '90s, the marriage was legitimately holding both characters back, reducing them to treading water.
When Grant Morrison took over writing the characters, he built his entire storyline around a love triangle between Cyclops, Jean, and reformed villain Emma Frost. Emma and Jean had a long, tortured history with each other, and were in many ways mirrors of each other. Emma had a cold and cruel exterior that hid a inner vulnerability and loneliness. Jean was all sweetness and nice covering an inferno of anger and a rather callous bully.
Cyclops had been possessed by an evil spirit, and shown his darkest nature. Jean didn't really seem to care, she acknowledged it happened but was far too busy with her own life. So Cyclops sought counseling from Emma. All his latent issues were brought to the surface, including the sexual dysfunction in his relationship with Jean. But the larger point Morrison was making was Cyclops and Jean had finally grown up to become two different people. Each had a particular trajectory and they didn't need each other. When Cyclops began his relationship with Emma, it was, despite two marriages, his first real adult relationship.
Emma pushed Cyclops. She helped him grow. As everything for mutantkind became worse and worse, she was the one who was able to bring out the version of Scott that could be an iron willed leader, a savior of a species. He couldn't be the highschool kid in love with his schoolmate, which is all he could ever be with Jean. That cancer that was introduced with Madelyne Pryor was finally excised by Emma Frost. It allowed Cyclops to become the dynamic center of the X-Men.
