I believe Rome expresses the matter like this: it is a discipline of the Latin Rite. The Byzantine Catholics, using the Eastern rite, are permitted the Eastern discipline of marriage for the priests (I believe, only before ordination).
That is correct. Marriage must take place before ordination. That is true also for non Latin Orthodox. Allowance for marriage is not universal for Uniate Rite Catholics. For example the Ukranians may not.
Peace, JOHN
So marriage is allowed as a ‘pre existing condition’ ... allowed because it would be a violation of marital vows to terminate the marriage because a man became a priest.
Not quite. It is allowed because the discipline is no marriage after ordination. In the Orthodox Church, bishops may not marry (some of us feel that may change over time), but priests may remain married if they were married before ordination. Essentially, it is a discipline, not a dogma, and so the Church is free to change it in either direction, either forbidding married priests (which I do not think will ever happen) or allowing married bishops (which might).
The reason for it, though, has to do with the development of the priesthood over time and, probably more pertinent to this board, the sacramental understanding of both marriage and the priesthood, as well as two practical concerns I'll touch on now -- ability to oversee the Church and concerns for lands held by bishops being transferred to heirs of bishops instead of the Church. Because I know very little about the history of both concerns, I'll just leave them here and let you all look into it as you will. I will also say celibacy carries with it another practical issue -- economics. Put simply, it is hard to support a priest and his family on what most parishes can pay. That, thus far, has not weighed against all the benefits to having married clergy in the Orthodox Church. I doubt it will.
As to the sacramental understanding, however, the call to the priesthood is considered a "higher" calling. Not that the priest himself is higher, but rather that the call to Holy Orders is beyond that of matrimony. It carries with it higher spiritual responsibilities. Some of these concerns led to the Latin rite practice of having only celibate priests. Because we share the concerns, but not the discipline, we allow priests to remain married if they already are, but do not allow them to become married once they enter the priesthood. For the same reason, a married priest who is widowed is not allowed to remarry, nor is his wife allowed to remarry if he predeceases her (because she by virtue of her marriage to him is a part of his priesthood, though she herself is not a priest). Similarly, a priest who divorces his wife, whether through his fault or hers, is defrocked, since the sacrament of nuptials is then broken. It would be like renouncing his baptism or disdaining communion.
