By the time of the Lateran Council (1139), marriage for most clerics had been in practice minimized or prohibited for 800 years. The Council of Nicaea (325 AD) had prohibited the presence in the house of a cleric of a younger woman (so called virgines subintroductae) --- clerics could only be honorably in the same house with a grandmother, mother, aunt, or sister.
In cities, most clerics lived in a shared household with other subdeacons, deacons, and priests, in a monastic-like community: there was no opportunity to court a woman, nor would their superiors permit it. Plus, even for priests who served alone in villages or the countryside, many local synods and many bishops prohibited marriage for all clergy within their provinces or dioceses, in order to avoid the worldly entanglements of dynastic marriage.
Let me explain what I mean by that. In addition to the overall prizing of consecrated virginity in both the East and the West, the West saw celibacy as a way to avoid political entanglements.
Moreso than in the East, the Church in the West had to wage a protracted struggle against secular power. Bishops were often landowners and way too enmeshed with the political nobility. (Look up “Investiture Controversy” and you will see that reforming popes struggled AGAINST this for centuries.) Marriage was very much about the alliance of families, and families were very much about the possession of landed estates.
If a bishop, abbot or prominent priest had sons and daughters, he’d be even more deeply caught up in dynastic marriage politics: marrying this daughter to that duke, and this son to that princess, and forming alliances with powerful families for all the political/economic/social benefits that would accrue.
Trying to secure the independence of bishops from the temporal Powers That Be was a huge job, it took centuries to settle and it’s not what I’d call “settled” even yet. But marriages would force priests and, even more so, bishops, to become even more deeply enmeshed in securing titles of nobility, access to estates and lands, royal alliances and the rest of it for all their children.
The Church in the West was striving mightily to steer clear of that whole web of entanglements. (Not so much in the Eastern Empire, which lasted 1,000 years longer than the Western Empire, and where Church and Empire were much more willingly and tightly interwoven.)
Celibacy --- the avoidance of ongoing dynastic interconnections --- became an honorable way to secure more political independence from temporal power, and hence more power to be “in this world but not of it.”
IN THIS CONTEXT, it came about that the Lateran Council outright prohibited clerical marriage. It has been "in practice" discouraged and even prohibited regionally, but there was too much unevenness of enforcement, and even worse, you had the scandal of priests living with women to whom they were not licitly or validly married. (These are referred to as "concubines" --- those in unlawful marriages.)
The Lateran, a reforming council, said "Let's make it plain, simple and official: clerics are to be celibate, period". They were simply confirming Church-wide what was already the practice established locally by synods and dioceses for centuries.
So it isn't a matter of Rome barging in and breaking up marriages and causing divorces. It was putting an end to clerical dynastic marriages and/or concubinage, on a Church-wide rather than regional basis.
Do you understand that?
What I understand about the RCC is it teaches and practices control.
What was happening prior to the Council is irrelevant.
The issue of can a person serving God be married is the main question. The Bible has no prohibitions on this. However, the RCC goes against the Bible, I guess because of that valued "tradition" the RCC uses to justify its non-Biblical teachings.