The kingdom of heaven and the life hereafter is nothing like what is here, and the metaphors used to describe it simply serve to assure the listener that material drives and needs will be of no concern. One asks if I marry the widow, whose wife is she in the afterlife.. its a foolish question, marriage ends at death, all physical things end at death, all emotions and possessive ties end at death; what is reborn is an entirely different existence. An existence that is truly suitable to sing to the glory of God.
I'm an atheist and don't believe in the afterlife, but I've always found some of the arguments against the afterlife to be a little silly.
You're right. Why would something like that matter when you are on a whole different plane of existence? How do you have those biological desires if you cease to be biological?