Source is Comic Creators on X-Men
In your mind, did Scott and Emma commit adultery?
The way I saw it was that Jean and Scott had become remote. For me, the great emotional moment for Scott and Jean was when they ran out to die together on the moon during the Phoenix Saga. After Jean died, Scott ended up with a lot of other women. Scott was very attractive to women even though he didn't know it and I wanted to play around with that. Since he was becoming emotionally remote from Jean, because she was becoming more and more godlike, it just seemed he would naturally fall into the arms of someone more emotionally connected, which Emma actually was. Yes, it was a kind of adultery, but at the same time Jean wasn't being his wife anymore. I just felt that the spark between them had died out and it was time to give Scott someone else.