I wonder when there might be an appropriate situation in real life to use this sentence :)
When you have invited your entire department and their significant others for a bbq party and your husband asks you if you know the significant others.....???
Suppose there is a sultan who has more than one wife. You want to say about the women, "I do not know their husband."
Isn't the Czech the same, namely, "Jejich muže neznám"?
As a practical matter, what would you actually say in this case?