How do I stop getting my wife's emails?

I gather you are not sharing an account? It may be that you added her email account to your list of accounts to use with Mail. See the article: Add an email account to your iPhone, iPad, or iPod touch - Apple Support

bu remove her account instead of adding one.

The other possibility is she may have set her email account to forward to yours. That would have to be undone from her end. How depends upon the service provider.

Refer to this document for ways to contact Apple --> Choose your country or region - Official Apple Support

Select your country (also look for "other" regions), then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service by telephone --> Contact Apple for support and service - Apple Support