It's a one to many reltionship. That's why. Yes auser can have an infinite number of email address, but an email address should belong to one user only. Why cr

It's a one to many reltionship. That's why. Yes auser can have an infinite number of email address, but an email address should belong to one user only. Why create a new user id that has to be unique and that I have to remember when I have this unique thing you can additionally use when I firget my password?