And what would you do with being married to a npc? What would you get out of it? Slightly different cinematics and a "widowed" status don't sound remotely engaging.

I suppose you can claim a retainer as your npc spouse, and at least they have an inventory that can help you. But really, this just sounds like a downgraded version of the Eternal Bond. At least you can actually role play or run dungeons with your bonded partner.