Ave Maria!
“The Immaculate is united with the Holy Spirit in an ineffable way, by the fact that She is His Spouse, but She is in an incomparably more perfect sense than this term can express in creatures. What kind of union is this? It is above all interior; it is the union of Her being with the being of the Holy Spirit. The Holy Spirit, in fact, dwells in Her, lives in Her, and does so from the first instant of Her existence, always and for all eternity.” (SK #1318)
It is more comprehensible to say that Mary is the Spouse of God or Spouse of God the Father, inasmuch as Jesus is the Son of
God the Father, and Jesus is the Son of Mary. Jesus was conceived by the Power of the Holy Spirit, but fathered by God the Father.