Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Council in Trullo; Often Called The Quinisext Council.: Canon XXX

p. 379 Canon XXX.

Willing to do all things for the edification of the Church, we have determined to take care even of priests who are in barbarian churches.  Wherefore if they think that they ought to exceed the Apostolic Canon concerning the not putting away of a wife on the pretext of piety and religion, and to do beyond that which is commanded, and therefore abstain by agreement with their wives from cohabitation, we decree they ought no longer to live with them in any way, so that hereby they may afford us a perfect demonstration of their promise.  But we have conceded this to them on no other ground than their narrowness, and foreign and unsettled manners.

Notes.

Ancient Epitome of Canon XXX.

Those priests who are in churches among the barbarians, if with consent they have abstained from commerce with their wives shall never afterwards have any commerce with them in any way.

Fleury.

(Hist. Eccl., Liv. XL., chap. l.)

“Priests who are among the barbarians,” that is to say, it would seem, in Italy and in the other countries of the Latin rite.  “Their narrowness and foreign and unsettled manners,” that is to say that according to them it is an imperfection to aspire after perfect continence.

I do not think that this explanation of Fleury’s can be sustained, and it would seem that Van Espen is more near the truth when he says:  “Some priests in barbarous countries thought they should abstain after the Latin custom even from wives taken before ordination.  And although this was contrary to the discipline of the Greeks, and also to Canon V. of the Apostles, nevertheless the Fathers thought it might be tolerated, provided such priests should also not live any longer with their wives.”  There seems no reason to introduce anti-Roman bitterness where it is not already found.