You need to consider that you will always have control of this account even though your other half will her own address and password. As the primary account holder you will be able to access her emails and change the password should you so choose. Also the email account will only work if you continue to be a VM broadband customer.
Given the above your wife may prefer to set up a new email address with a free email provider not linked to your ISP.
_________________________________________________________ Graham I am a VM customer. There are no guarantees that my advice will work.
As a Very Insightful Person, I'm here to share my knowledge. I don't work for Virgin Media.