“Mary was the only one who merited to be called the Mother as Spouse of God.” St. Augustine of Hippo, in Sermons #208 (quoted by St. Alphonsus de Liguori in The Glories of Mary, p 304 (New York: Redemptorist, 1931).
“…St Godfrey of Admont wrote that each person of the Godhead is Mary’s lover.” See the book by Michael O’Carroll, titled “‘Spouse of God’, Theotokos: A Theological Encyclopedia of the Blessed Virgin Mary”, p 158 (Wilmington, DE: Glazier, 1982).
Mary is the Bride and Spouse of God the Father
"…the mother of the Son of God can also be called in a special manner ‘bride of the Father.’ For, as mother she has received the Son of the Father through donation from His side as her Son; she possesses Him conjointly with the Father and is therefore connected with the Father by His Son as being hers also. (Fr. Matthias Joseph Scheeben, in Mariology, vol. 1, p 174-175 (“nihil obstat” by Innocentius Swoboda, O. F. M. Censor Librorum, “imprimatur” by Josephus E. Ritter, S.T.D., Archiepiscopus).
“Thus St. John Damascene, an outstanding herald of this traditional truth, spoke out with powerful eloquence when he compared the bodily Assumption of the loving Mother of God with her other prerogatives and privileges…‘It was fitting that she (Mary), who had carried the Creator as a child at her breast, should dwell in the divine tabernacles. It was fitting that the spouse, whom the Father had taken to himself, should live in the divine mansions.’” Pope Pius XII, in Munificentissimus Deus (Defining the Dogma of the Assumption), Encyclical promulgated on November 1, 1950, #21.
papalencyclicals.net/Pius12/P12MUNIF.HTM
Mary is the Bride and Spouse of God the Son
“Saint Ephrem the Syrian was probably the first early Christian to refer to Mary as the Bride of Christ…He was followed by the likes of Saint Peter Chrysologus, Rupert of Deutz, and Godfrey of Admont.” See the book by Michael O’Carroll, titled “‘Spouse of God’, Theotokos: A Theological Encyclopedia of the Blessed Virgin Mary”, p 333 (Wilmington, DE: Glazier, 1982).
“…(Mary is) the unique bridal, permanent helpmate and associate of Christ, who is the Head of the whole Church and world, in the entire work of redemption…” Fr. J. Kentenich, in Der Marianische Priester, p 38 (1941).