In a twisted way, it's really rather romantic. Both too stubborn to ever give in to each other's whims. Two old dogs refusing to learn new tricks. They never knew too many in the first place.
They seemingly hate each other. No love is clearly apparent, but there's this obdurate will; this obstinate sense to stick together through thick and thin. They really must have taken those vows seriously.
It's like two gnarled trees that grew in tandem. Trunks and limbs twisted towards the light of some shifting sun. Any attempt to remove either of the two, would surely result in the death of the other one.