Contact Management Database Help

Hi all,

I am well versed in Excel/VBA design, but I'm relatively inexperienced with Access, so I'm hoping someone here can point me in the right direction.

I am working on a project to create a contact management database to house several hundred clients to store some basic info (name, company, email address, etc). I started with the Microsoft template, as it has most of the functionality I need:
Desktop contacts - Templates - Office.com

The biggest addition I need to make is to allow us to track what subscriptions each email address has - one email address can have several subscriptions. I've been messing around, and modified the form to allow checkboxes that store data in the Contacts table, like so:
Form modification
Contacts table

But now the Contact List page lists multiple records for each subscription I add, and I'm getting an error whenever I modify an existing subscription:
Two subscriptions, two rows
Error: The field is too small to accept the amount of data

Any advice? Did I even set this up correctly conceptually? Any help is appreciated.