56 It is well that He seeks your beauty within, where He has given unto you power to become daughters of God: He seeks not of you a fair flesh, but fair conduct, whereby to bridle also the flesh. He is not one unto Whom any one can lie concerning you, and make him rage through jealousy. See with how great security ye love Him, Whom ye fear not to offend by false suspicions. Husband and wife love each other, in that they see each other: and what they see not, that they fear between themselves: nor have they sure delight in what is visible, while in what is concealed they usually suspect what is not.
You in Him, Whom ye see not with the eyes, and behold by faith, neither have what is real to blame, nor fear lest haply ye offend Him by what is false. If therefore ye should owe great love to husbands, Him, for Whose sake ye would not have husbands, how greatly ought ye to love? Let Him be fixed in your whole heart, Who for you was fixed on the Cross: let Him possess in your soul all that, whatever it be, that you would not have occupied by marriage. It is not lawful for you to love little Him, for Whose sake you have not loved even what were lawful. So loving Him Who is meek and lowly of heart, I have no fear for you of pride.
Source: On Holy Virginity (New Advent)