email account providers do not give out information about their account holders.
One thing you could try is to perform an internet search on your boyfriend's name, or IDs you know he uses, and see what comes up.
This might find something, but won't necessarily find what you're looking for.
If you feel your boyfriend has email accounts he's not telling you about, and you think this is cause for concern, you really need to ask your boyfriend about this.
If you're not happy with his response, you need to consider your relationship as it stands, and think about whether you should contemplate either redefining the relationship or even ending it.
Having said that,
How to find more than one address
The benefits of setting up an account with BT email is that a BT email account which is a secure email account with all the benefits of another account on more common email addresses.
you can't do it if you delete your account then no more email address
you will get a roadrunner email address once you sign up for their high speed online service. you will also get 4 more email addresses (subusers) under your account.
basically, an email account. and more importantly you should know how do to use it.
It isn't necessary and is often confusing to have more than one email account. It may be useful in separating work from personal communications.
give me your account i promise i will not change your password but ill get you like 90k or more email your account to me my email is hedeyasu@gmail.com
You can have more than one character in your swtor account, but not more than one swtor account on your email.
no
Yes, you may have multiple WikiAnswers accounts. Many Supervisors have another account so that they can browse the site as a Non-Supervisor. Some users choose to have more than one account if they have multiple email addresses. You can only have one account per email address. One thing that is not allowed is using multiple accounts to abuse the site. If you lose an account and the supervisors find out you have another account, then any violations at all using the new account may get it banned too.
Yes, because you are starting another account. You can only have one Moshi Monster for each account, but you can have more than one account even if you use the same email account to sign up.
You can either contact the email provider and ask for your account to be deleted, or simply stop using the account. Most email providers delete accounts that have lain dormant for more than six months.