As Fr Scott Whitmore points out, it comes down to a question of trust:
I was already on board with the TAC in our request to the Holy See to carry on Anglican-Roman Catholic ecumenical relations (knowing that these could not go forward with any part of the Canterbury communion that purports to ordain women to any of the Holy Orders), and to seek a way that we might come into communion with them corporately, while of course retaining our Anglican patrimony. I heard probably more than my share of rumors, but I had no firm idea of what form such reunion might at last take, or when it might come. I carried on with my ministry, with additional prayers for our House of Bishops, and for all involved both on our side and on the Roman side. After all, as my own Bishop has said many times, we are being obedient to the High Priestly Prayer of Our Lord as recorded in John 17. How could I do otherwise as a minister of the Gospel?
Meanwhile, the Holy Spirit was preparing me. I came into the Anglo-Catholic fold, as many of my brothers and sisters have, from the conservative Protestant end of the spectrum, and I have had many of the usual difficulties with Catholic teaching. Over the years, I had gradually warmed to the classical conclusions on divorce and contraception, and more recently, to the teachings about Our Lady and a fuller appreciation of the Communion of the Saints. It has also become increasingly obvious to me that — faults notwithstanding — the Roman Catholic Church is, and the Bishop of Rome is, the best teacher and defender of the truths of the Faith in the world today, lending strong circumstantial evidence to the already plausible thesis of papal primacy. I also have noted with grief that it is becoming increasingly difficult for Anglo-Catholicism to subsist separately: we are more and more ruthlessly being squeezed out of the Canterbury communion, and the Continuing Anglican movement has proved rather less successful than hoped. But at the same time, I was not (and am not) willing to sell short the treasures of our liturgy, our discipline and order, our spirituality, our music, etc.
Anglicanorum Coetibus is all that we could have hoped. . . .