These words (about virginity being desirable) are not meant for everyone, but only those to whom God gives the grace to be chaste.
Saint Paul was a virgin, and wished that everyone could be virgins, but this was only a recommendation (implied: not a command) of virginity.
He gave the Wife permission to be a Wife. Therefore it is no sin for her to marry again if her husband dies.
Even though Saint Paul said it was better not to touch a woman, he only meant in bed or on a couch, because that's like putting together flame and tinder.
Saint Paul thought virginity was more perfect than wedding in frailty (i.e., than getting married because you want to have sex).
The Wife of Bath calls it frailty unless both woman and man are chaste for their entire lives. (This part is ambiguous. She is probably saying that, if someone has already been married once, they have already given in to frailty and so might as well continue to do so by marrying again.)