Users cannot currently hide/ignore certain media (although there’s a feature suggestion asking for such an option).
That leaves you with restricting what you share with the account of your wife… e.g. applying a restriction based on labels you assign to items — either sharing only items with a specific label (whitelisting) or hide items with a specific label (blacklisting).
https://support.plex.tv/articles/204232573-restricting-the-shares/
