How can my husband and I share all of our contacts

A solution would be to use a 3rd party email account that offer Contacts functionality, Gmail for instance. This mail account could be added to both your devices and you could both use the Google list in Contacts to see the same list of contacts.

No, sorry, Apple doesn't offer this option.

You can share a contact one at time using AirDrop but those shared contacts are not synchronized (if you were to edit one on one device, it would not be reflected on the other device.)