I know of so many failed marriages between "spiritually strong" JWs, proving that a mutual love of "The Truth" is NOT all that's needed for a successful union. I can remember one particularly disastrous marriage that was annulled within about a week or so. I never found out the gory details other than they realised on their wedding night that a terrible mistake had been made! The mind boggles!!
When you take into account their belief that they are destined to spend forever in the New System with each other, how cruel and irresponsible to marry them off without allowing them to make sure they are thoroughly compatable. Obviously it is far better for them to spend eternity with someone totally unsuitable, who they only married out of desperation for a bit of nookie, than to risk touching each others' naughty bits without a walk down the aisle first!