Thank you, Gingerymoon, for taking the time to respond! I appreciate your feedback.
In my current household I have 4 out of 6 sims in the Noble Career. Two of them are low to medium in the Noble career. I have tried demoting and promoting the husband to different levels of the Noble career (using MCCC), and in all of them his wife is still the rival.
Oddly enough, the other household members (who are relatives and in the same dyansty under the Queen's Headship over this dyanasty), neither of them see her as a rival, which is odd to me. You'd think the brother & nephew would see the Queen as a Rival; and the Husband, who has title King becasue of his marriage to her, would not see his wife as a Rival.
I am thinking this must be a glitch. Even after trying a Wedding Ceremony between them the Rival status did not change.
Also a note, the wife/Queen does not see her husband as a Rival. Only the husband/King sees his wife as a Rival. I think that's becasue she is higher ranked than him in the Noble career, and only one person can be in the Level 10 Monarch role.
It still doesn't make sense for the King to see his wife as a Rival. (At least the way I am trying to play. Maybe others enjoy their Sims' marriages fraught with rivalry, lol.)
I am still hoping there will be some update to fix this issue. An option to to check/uncheck for Spouses/Patners are Never Rivals in the Noble Career.
Thanks again for your response! I hope you have a lovely day! 💐