Hello,
Using a mailing list software package instead of an address book contact list might work better for you. Some are free, some cost money, but one of the standard features is an automatic unsubscribe mechanism for email address that are invalid or bounce several times in a row. How are you storing your list of addresses now and how are you sending the email to them? Who provides you with your email account and SMTP server? It's unlikely that a residential ISP has an option to help you with this but it's possible. Do you know what limits your ISP has for the number of email you can send in a day and/or the number of recipients that are allowed per email?
-Raymond