//But I wasn’t aware that Catholic priests had a choice to not be celibate and was strictly ”voluntary.”//
In Western rite, they must remain celibate in order to remain priests. However, in the Eastern rite, they can be married. If an eastern rite priest moves over to the western rite, than can remain married. Several years ago, many Western rite priest would go over to the Eastern rite to get married, stay awhile and then move back to Western rite - however that has now been restricted.
I believe the Eastern rites of the Catholic Church allow a married man to become a priest, but do not allow a man who is already a priest to marry. So if a married priest becomes a widower, he cannot remarry.