Christ’s bride is the Church (and in a sense, our souls), and it would have been a bit weird if Jesus had fathered children. Would they be some sort of demigod? I don’t think you’re wrong that there were practical reasons for it, but I think it goes much deeper than that.
But, if I am not mistaken, marriage wasn’t always denied to Catholic Priests. I think hundreds of years ago Catholic Priests were allowed to marry, were they not?
Yes, they were. It was more rigorously enforced in the 11th century when priests were creating dynastic parishes (passing the parish on from father to son), which was causing problems. Celibacy has always been encouraged, though, and was quite common before that as well. Eastern Catholic priests still don’t have to be celibate. From what I know from speaking with them and hearing about their situations, however, many of them do run into conflicts between their family and parish, and it’s clear that there’s a lot of practical wisdom in celibacy.
All the seminarians I’ve talked to about this agree, by the way. They all think that making celibacy optional would be a bad idea, and would create more problems than it would solve. We want to be as free as possible to serve the Church and God. Being a married priest is a bit like a having two wives. Sure, people have made it work, but it’s really hard to balance the two.