They're in a creative industry and this is very much their company culture. It's a very successful company so I guess it's working for them, though I do tend to agree I think it's a bit weird. I don't know if all of the contacts will get the joke of work wife/work husband, but it's just a super campy family Christmas card. You know, matching sweaters in front of the fireplace and forced smiles type thing. So I get that it's a joke in itself even with out the knowledge of their interpersonal relationships.

But at the same time, I and a lot of people they work with do know about those interpersonal relationships, which is why I think it's inappropriate.