I think your wife should read the entire
Catechism section dealing with the Fourth Commandment. It is an important analysis of the family in God’s plan, along with its limits.
Pay particular attention to:
2217 As long as a child lives at home with his parents, the child should obey his parents in all that they ask of him when it is for his good or that of the family. "Children, obey your parents in everything, for this pleases the Lord."22 Children should also obey the reasonable directions of their teachers and all to whom their parents have entrusted them. But if a child is convinced in conscience that it would be morally wrong to obey a particular order, he must not do so.
As they grow up, children should continue to respect their parents. They should anticipate their wishes, willingly seek their advice, and accept their just admonitions.
Obedience toward parents ceases with the emancipation of the children; not so respect, which is always owed to them. This respect has its roots in the fear of God, one of the gifts of the Holy Spirit.
2230 When they become adults, children have the right and duty to choose their profession and state of life. They should assume their new responsibilities within a trusting relationship with their parents, willingly asking and receiving their advice and counsel. **Parents should be careful not to exert pressure on their children either in the choice of a profession or in that of a spouse. **This necessary restraint does not prevent them - quite the contrary from giving their children judicious advice, particularly when they are planning to start a family.
And this on the Sacrament of Marriage:
1605 Holy Scripture affirms that man and woman were created for one another: "It is not good that the man should be alone."92 The woman, “flesh of his flesh,” his equal, his nearest in all things, is given to him by God as a “helpmate”; she thus represents God from whom comes our help.93 "Therefore a man leaves his father and his mother and cleaves to his wife, and they become one flesh."94 The Lord himself shows that this signifies an unbreakable union of their two lives by recalling what the plan of the Creator had been “in the beginning”: "So they are no longer two, but one flesh."95