I’d never write a future relationship as trying to overcome Scott and Jean's love. Their relationship is just too good to be overcome, which is why I'd always keep them together.
But if I had to write something else, I’d write any further relationship as interesting as it can be, without making comparisons or trying to convince the readers that the current one is better. That would never work.
My favourite pair for Jean, if they ever break their marriage apart, would be Warren. He never forced himself on her even though he carried a torch for her (at least) up to the day she got married. But he never said a word about it. Instead, he learnt to be be happy for both his friends. He's such an awesome guy!
He was a hero before he was an X-Men. He has his own experience with alternate personas and identity struggles. He was always there whenever she wanted to try something and he’s not afraid of trying new approaches himself. He’s brave and fun and loyal and I believe they’d be great together.
And I don't think it would be weird when it came to Scott, because it's not like Warren became his friend after he was in a relationship with Jean already. Meaning, when Warren met Jean she wasn't Scott's girlfriend. They both met her on the same day and they both fell for her at the same time. So I think it's fair. And I think if Scott would be okay to see Jean with someone else it would be Warren, exactly because he knows Warren is a great guy.
Like I said somewhere else, they’d get to spend his fortune on crazy charitable projects and mutant outreach endeavours, they’d attend glamorous parties and diplomatic meetings, they’d fly all over and they’d make the cutest redhead cherubs ever.
And that’s how I’d frame it. I wouldn’t have Jean constantly saying: “You’re so much more fun than Scott, War” or “I actually love that you love dressing up” or “And imagine that! You prefer to spend the night in bed with me instead of working your worries in the Danger Room or fixing something like Scott. You’re so easy going, my Angel”. Ugh…