The fact that it is an Apostolic Norm means that it was unilaterally changed at Trullo for the Eastern Catholics.
The disciplinary canons of the Council of Elvira in 305 are the Church’s earliest record regarding priestly celibacy. The council gave no explanation of its rulings, which were ancient and presumably well-known. Canon 33 forbade all married bishops, priests, and deacons from having sexual relations with their wives and begetting children. The council reminded the married clergy that they were bound by a vow of perpetual continence. Penalty for breaking that vow was deposition from the ministry. Commenting on this council, Pope Pius XI said that these canons, the “first written traces” of the “Law of Ecclesiastical Celibacy,” "presuppose a still earlier unwritten practice. " (*Ad Catholici Sacerdotii *, 43, 1935).
Not only is the celibate priesthood from Christ, it is most scriptural:
St. Peter asked Our Lord, “What about us? We left all we had to follow you.” The Divine Master answered: “I tell you solemnly, there is no one who has left house, wife, brothers, parents or children for the sake of the kingdom of God, who will not be given repayment many times over in this present time and, in the world to come, eternal life” (Lk 18:28-30, cf. Mt 19:27-30; Mk 10:20-21).
The Magisterium teaches:
32. This doctrine of the excellence of virginity and of celibacy and of their superiority over the married state was, as We have already said, revealed by our Divine Redeemer and by the Apostle of the Gentiles; so too, it was solemnly defined as a dogma of divine faith by the holy council of Trent,[57] and explained in the same way by all the holy Fathers and Doctors of the Church. Finally, We and Our Predecessors have often expounded it and earnestly advocated it whenever occasion offered. But recent attacks on this traditional doctrine of the Church, the danger they constitute, and the harm they do to the souls of the faithful lead Us, in fulfillment of the duties of Our charge, to take up the matter once again in this Encyclical Letter, and to reprove these errors which are so often propounded under a specious appearance of truth.
(
Sacra Virginitas, Encyclical Of Pope Pius XII, 1954).
‘In her magisterial statements, the Catholic Church has often spoken of the Eastern practice regarding celibacy. The Church always uses guarded language, not wanting to widen the breach between the Orthodox Churches and the Catholic Church. But she has never said—never even implied—that the Eastern practice stands on par with her own discipline regarding celibacy. Typical of her attitude is the language of Pope Pius XI in his 1935 encyclical on the Catholic priesthood. After extolling the glories of priestly celibacy, he said he was not criticizing the Oriental discipline. “What we have said has been meant solely to exalt in the Lord something we consider one of the purest glories of the Catholic priesthood , something which seems to us to correspond better to the desires of the Sacred Heart of Jesus and his purposes in regard to priestly souls” (
Ad Catholici Sacerdotii, Section 47).’
vatican.va/holy_father/pius_xi/encyclicals/documents/hf_p-xi_enc_19351220_ad-catholici-sacerdotii_en.html