You should try and find out who is giving your wife attention that is causing her to think that you are replaceable. It could be a neighbour or something.
Yes, it will end badly. Most times it does.
It is probably not a single person. More likely: A hundred little "likes" or whatever they call them received daily on Instagram, Tik Tok, or whatever. A hundred little nudges from online influencers or legacy media telling her to "you go, girl!"
She is receiving all kinds of implicit and explicit "suggestions" all the time, that she indiscriminately swallows.
Regards,