Well, I think you are getting at something that should be called a household, not a marriage. (I mean for the government sanctioned arrangement, not the church or religiously sanctioned one.)
My point is that Ireland just legislated a tax ID, or a household, if you will.
Only God can solemnize a marriage, and no one accepts another’s faith for that. It’s about time people got more specific about these things - they’ll use less blood pressure medication.