From a reader:
For the sake of argument, couldn’t a married Catholic man, who wanted
to become a priest, simply get around the un-married rule by seeking
ordination in an Episcopalian/Anglican seminary and after ordination simply take advantage of John Paul II’s provision to Anglican clergy and be ordained as a Catholic priest?
Holy Church has already thought of that eventuality.
A Catholic who apostacizes and becomes a minister of some other group, and comes back into communion of the Church is brought back by the Church “ut laicus“, as a layman. He will not be permitted to exercise even valid orders.