1) Unless your daughter is a minor, you don’t get to have requirements for her prospective spouse. Not only do you not get to choose him for her, you have no veto power over her choices at all. None. You don’t get to lay down criteria. You don’t get to say, “He has to be Catholic,” much less, “He has to have a prayer life.” However reasonable the demand may seem to you, and however objectively advantageous to your daughter, you have no right to insist that the man seeking her hand in marriage be gainfully employed, or have no debt, or come from an intact family. All of that is out of your hands completely and totally. If you want to have good relations with your daughter and future son-in-law, strive to realize that fact deeply and sincerely. Be sure that your words and actions reflect it. If they haven’t, or don’t, repent—to God and to her. You were out of bounds.
2) Your adult daughter doesn’t belong to you; she belongs to herself. Her decisions—especially those relating to her intimate life and her prime vocation—must be her own. If you want her to be properly self-standing, rather than weak and dependent in relation to men, you should take care not to influence her too heavily. As she is growing up, work to develop her independence; encourage her to choose freely, and for herself, according to her own sense of right. Make a point of expressing confidence in her ability to discern God’s will and choose well. (Make sure you don’t give her the impression that choosing well means choosing according to your ideas.)
3) Your daughter is not a better daughter if she tries to conform to your judgments and preferences. Her responsibility as a person is not to live the way you think she should, but to live the way she thinks she should. Don’t make her have to fight you off to figure out who she is and what she wants in life. Don’t crowd her discernment with your judgments. Don’t put pressure on her to see things your way. Don’t confuse her morally by acting and talking as if you know better than she does what’s best for her. You don’t; you can’t. The moral life is lived “from within.” It’s better by far for her to make her mistakes and suffer the consequences than to live into adulthood under her father’s thumb, however benevolent a thumb it may be. Just as a young man “tied to his mother’s apron strings” is crippled in his manhood, a daughter under her father’s thumb is crippled in her womanhood.
4) Rejoice if your adult daughter asserts herself by defying your illegitimate “requirements”. There is nothing wrong with her resisting your undue interference in her life. On the contrary. It indicates that she has the self-respect and inner stuff to demand respect from men. This is good. Just as men have a particular call to restrain the natural tendency to dominate women and instead order their gifts toward love and service, women have a particular call to resist their natural inclination to be servile and dependent. They must learn to assert themselves against anyone who tries to dominate them, wittingly or unwittingly. This includes their fathers. It includes their future husbands. If she can assert herself lovingly, without anger and bitterness, great. If she can’t, it may be because your heavy-handedness has made smooth relations between you impossible. In any case, it’s better that she does it. As Chesterton said, “Anything worth doing is worth doing badly.”
5) Her prospective fiancé doesn’t have to ask your permission before he proposes. He doesn’t even have to ask for your blessing and approval. There is no disrespect whatsoever toward you implied in his asking her before he asks you. On the contrary, by acting as if it’s your prerogative to be asked at all, you express an inexcusable disrespect toward them.
6) Don’t let your prospective son-in-law behave toward you as if you have authority you don’t actually have. That would set you both up for dysfunctional relations. If he asks your permission to marry your daughter (perhaps out of immaturity or romantic nostalgia, or undue deference), your answer should be something like this: “My daughter speaks for herself. If she says yes, you will both have my blessing.”
7) However attached we may be to the tradition of prospective husbands first asking the father for his daughter’s hand in marriage, we should realize that it comes from an age when single women were legally and economically dependent on their fathers. They could not marry without his permission. That that is no longer the case—that a woman’s right to dispose freely over her own existence, in accordance with her dignity as a person—is a great moral achievement of the modern age, endorsed by the Church and incorporated into her teachings and traditions. (See John Paul II’s Letter to Women.) Mature Christians adapt customs to new moral understanding. We don’t try to conform reality to our preferred customs.
8) If you decide to withhold your blessing from her choice, your reasons had better be serious enough that you are prepared to lose your daughter. If he has shown himself to be a liar or a two-timer or an addict or an abuser or a blasphemer, you can’t bless the marriage. You can share your concern with your daughter, though. And you can pray.