I'm still not sure whether Jean having an identical mental affair with Logan in X-men Forever agrees with Morrison's point that they'd soured as a couple, makes Scott AND Jean look like asses, or both. It's interesting to hold up Scott's reaction to Jean's affair with Logan in that book against Jean's reaction to Scott and Emma though.
Scott's affair with Emma was undoubtedly low, it wasn't out of character. He's always been flighty with women, which always put the Jean and Scott forever! romance and styling them as one of Marvel's greatest couples on shaky ground, especially when Jean never seemed to discourage Logan either.
I don't think this story did any of the characters any favours, but I don't think the marriage was something that should never be broken, funnily enough, given my feelings about Peter Parker and Mary Jane.