This is odd. Have you checked the password in the incoming server settings on your client, to ensure it matches the one you input into webmail?
Also, is your wife able to access webmail with her email credentials?
Post an update on here so we can decide if further support is needed. Though I would probably advise that you log in to My Virgin Media with the primary email account and change passwords for all accounts.
I'm not sure why this happened to be honest, though I suspect perhaps an issue with weak passwords? But I'm glad it's all working for you now, thanks for the update and do come back to us on here if you need help with anything else.