How to add a secondary email address for a user

Ultimately what I’m trying to accomplish is to have push notifications or text messages sent to members of a BuddyPress site on various actions. For example, when a new post is published, when group activities are shared (using the group email plugin). I was wondering if there is some way that WordPress/BuddyPress users can have 2 email addresses. The solution in this case would be to add a secondary email/phone address (i.e. Thoughts?