Since the tradition of the Church (including virtually all the early Protestant reformers, by the way) included the perpetual virginity of Mary, there is no reason to prefer an explanation that contradicts that belief, which was universally held until VERY recently (I think the religious wars in England is the first place the rejection of Mary's virginity crops up, among the Levellers and Fifth Monarchy men).
But, seriously, would YOU touch the Ark of the Covenant in that way? Remember what happened to Uzzah . . . .
But if we have to make up a couple of possible explanations (because Scripture is not explicit on the question), why don’t we just assume that after Christ was born, Mary had other children the regular way? I can’t see how that taints her special calling from God to be the mother of the Messiah. I’m not arguing just to argue, I can’t see why it’s so important to maintain her virginity when Scripture doesn’t explicitly support it. It does not detract one whit from her status, IMHO.