Get off this forum right now!
This has been the practice of the Church for 2000 years. Thats why it is in the moral theology books of the Church. All explained.
Go ask your priest. If you go to an SSPX Mass that might be a problem.
The Church has allowed many practices that are of human tradition to continue, even if they are not in line with Christ's teachings. This human tradition that men are the head of the household and have the power of life or death over that household (spouse, children, servants and slaves) has been civil law for centuries, but these civil laws have been abused with many children and wives being killed, even today, especially in Muslim countries.
This is very troublesome. It appears as if some men on this forum are adapting Islamic ideas, instead of putting on Christ, controlling their passions, and praying unceasingly. These men want to marry young women who are rated 10 out of 10, and be able to beat any relative who disagrees with them. They appear to be very narcissistic -- me, me, and more me.
If husbands and wives were to pray together and pray unceasingly as St. Paul urges, many of these urges of men to spank or use violence in a rage would not take place. Violence and violent tempers are not of Christ. Instead a firm look and a simple sentence, "Stop, we need to pray" would be adequate.
Yes, sometimes corporal punishment may be necessary. Did not Christ chase the money-changers from the Temple using whips? But the money changers were not family, and family ties and filial love can be broken by the violence of spankings or worse, severe beatings.
Temperance, patience, meekness, humility, and love are manly virtues that need to be inculcated in the family. The husband should lead by example, not by his fists.