Add 2nd email to profile/share account

Give the possibility to create a 2nd e-mail field. Some clients like to have the mails also sent to the partner because they take classes together or take turns.

Is it possible for one customer account to be managed by two people? we have a couple that has split up and have co-parenting of the dogs. They don't want one to have the password of the other. Or two accounts and that the same dogs are in them. But not that the dogs are in the system 2x? ivm double booking.