Originally Posted by
FUBAR007
Scott and Jean became a couple in 1967 with X-Men vol. 1 #32. They remained a couple until #101 when she was replaced by the Phoenix. That was 1976, so 9 years initially. Scott was then with Phoenix-Jean until her suicide in #137. That was in 1980. So, depending on how you interpret the Jean/Phoenix retcon, that's potentially another 4 years.
Jean was resurrected in 1986. When exactly she and Scott qualify as "back together" is fuzzy and open to interpretation. Their first post-resurrection kiss is in X-Factor vol. 1 #13 in 1987, but that's just before Scott leaves to go back to Madelyne in Alaska. Of course, due to Sinister's shenanigans, all he finds is a corpse, and he's back in New York with Jean two issues later. The two of them (re?)consummate their relationship in #26 in 1988. From there, there are ups and downs, but they remain as a couple until Morrison's run, having married in 1994. Just when Scott and Jean no longer qualify as a couple is also fuzzy and up for debate. They were still married all the way up until Jean's death in New X-Men vol. 1 #150 in 2004. But, their relationship was already on the rocks when Morrison's run began in 2001. So, a minimalist interpretation would have them together from 1988-2001 i.e. 13 years; a maximalist interpretation would have them together from 1987-2004 i.e. 17 years.
Except for that brief scene in Phoenix Resurrection #5, they haven't been a couple since.
However, there are two potentially complicating factors: Scott's marriage to Madelyne and the relationship between Tyke and Jeen.
Madelyne was Jean's clone and animated by a fragment of Jean's soul. Therefore, there's an argument to be made that Scott and Madelyne's relationship was just an iteration of Scott and Jean's relationship. Also, Jean absorbed Madelyne's consciousness and memories at the end if Inferno. Scott and Madelyne were together from Uncanny X-Men vol. 1 #170 in 1983 to X-Factor vol. 1 #1 in 1986. So, that's potentially another 3 years.
Tyke and Jeen is even fuzzier. I don't recall them ever being formally together except for their kiss at the end of X-Men Blue. But, they were very close at points throughout Bunn's run. Then, there was that bit where they shared the psychic rapport for a while. OTOH, Scott was dating Bloodstorm there for a bit, too.
My personal opinion: the Phoenix-Jean years count, but the Madelyne years don't. Scott and Jean basically got back together when he came back from Alaska thinking Madelyne was dead. As far as Morrison's run, Scott and Jean were still married and still loved each other, even if they were both acting like immature idiots, all the way up to her death. I don't think Tyke/Jeen counts because it was more that they were building toward getting together than being together.
So, IMO: 1967-1980 (13 years) + 1987-2004 (17 years) = 30 years total.
For comparison, Scott and Emma's romantic relationship began with her seduction of him in New X-Men vol. 1 #131 in 2002. They remained together as a couple until AvX in 2012. While they continued to work together off-and-on until his death in Death of X, they weren't intimate. So, Scemma lasted 2002-2012 i.e. 10 years.
616 Jean and 616 Logan have never been together, so they're a zero. Scott and Betsy flirted and kissed once, but they were never together, either. So, another zero. Jean and Bishop have been a couple so far for just the Age of X-Man event which has lasted less than a year. The next closest rival relationship in terms of length would be Scott and Lee Forrester, but that amounted to a couple of flings over a couple of years.
The only substantial rival to Jott is Scemma. Even under the minimalist definition of Jott--1967-1976 (9 years) + 1988-2001 (13 years) for a total of 22 years--lasted more than twice as long.
Scott's never been with anyone as long or longer than he's been with Jean.