The deviation from tradition came as a subtle shift in the understanding of the primary end of marriage.  Pope Paul VI, in his encyclical Humanae Vitae, focused on the physical aspect of marriage and noted two ends, the procreative and the "unitive."  He omitted the traditional understanding of the primary end.  In addition, he promoted the novel concept of "responsible parenthood" which includes deliberately avoiding procreation.  This has grown into the practice known as natural family planning, or NFP.  Hence, by abandoning traditional theology, we now have Catholic birth control (which is 99% effective, you know!).

Another consequence is a diminution of the marriage of St. Joseph and the Blessed Virgin.  For if the ends of marriage are two-fold, then the marriage of Mary and Joseph was lacking.  Continuing on this faulty path, some posit the "unitive" aspect to be holy, and discard the traditional understanding that celibacy is the higher calling.  And further down this path, some devote themselves to study of a so-called "theology of the body."  Do you imagine that such an oxymoronic concept could have arisen had Thomistic philosophy reigned supreme?

Pray for a renewal of scholastic philosophy and a restoration of the traditional understanding of marriage.