Oddly people are permitted to have relations with other than their first spouse: If they are widowed, or if they merely quietly commit adultery without a remarriage, or if they convert to Catholicism after their second marriage. The church doesn’t want to endorse divorce, but if they don’t have to take a position, well, that isn’t their problem.
One fellow became a deacon, and his wife died. Because he was a deacon he was not permitted to remarry. He eventually was called to became a priest, and was very effective when counseling widows/widowers because he had been there.
Of course.
".. or if they merely quietly commit adultery without a remarriage..."
You can't exactly say it's "permitted" if it's "quietly," -- no serious sin like that is "allowed" but quite probably the priest doesn't know anything about it. Mortal sin disqualifies one from Communion --- it doesn't take an e-mail from the pope or a proclamation from the pulpit! --- and anyone conscious of being in mortal sin who receives Holy Communion, is committing a sacrilege: one mortal sin on top of the other.
"... or if they convert to Catholicism after their second marriage. "
That depends on whether their previous marriages were valid. Baptized Christians married in other (Christian) churches, and then divorced, could not remarry another spouse after conversion to the Catholic Church, unless the previous attempted marriages were annulled.
"The church doesn’t want to endorse divorce, but if they don’t have to take a position, well, that isn’t their problem."
The Church doesn't hire PI's and pro-actively investigate everybody in the church to see what their previous marital history was, or what their present domestic relations are. It only becomes an issue if they bring it up (e.g. by asking about annulment or remarriage) at which time the Church has to investigate via the Diocesan Marriage Tribunal. And even that can;t be done without the active and willing cooperation of the parties involved. The Church has no power to subpoena witnesses!
"One fellow became a deacon, and his wife died. Because he was a deacon he was not permitted to remarry. He eventually was called to became a priest, and was very effective when counseling widows/widowers because he had been there."
That's good to know, We have three terrific deacons at our parish, two of them married men and one of them a widower. I love these guys!