Judie Brown at EWTN — She points out that the use of any form of contraception is immoral, and, when contraception is used in sex outside of marriage, there are two wrongs: contraception and extra-marital sex.
Fr. Richard Hogan at EWTN — He takes essentially the same position. When contraception is used outside of marriage, both acts are gravely immoral. “Intercourse outside of marriage is seriously sinful. Contraception within or outside of marriage is seriously sinful.”
E. Christian Brugger — He answers the question: “Does the Catholic Church’s condemnation of contraception bind only on married couples or is it a universal moral norm?”
His answer is that contraception is intrinsically evil; it is gravely immoral regardless of marital state. “If contraceptive acts were wrong for married persons, but legitimate for unmarried persons, they would not be wrong per se, would not be intrinsically evil, but circumstantially evil. Although some Catholics hold this, the view seems clearly to be inconsistent with both the Church’s theological and doctrinal traditions.”
Christopher O. Tollefsen — In my post, I review Tollefsen’s position on this question, which can be summarized by these quotes: “contraceptive acts are intrinsically wrong, and not merely always wrong within the marital context,” and, “tradition as a whole has also consistently treated contraception as wrong outside of marriage.”
Catholic Answers — The question: “Does Humanae Vitae state that birth control is only forbidden for married couples?”
The answer: Contraception “is always objectively evil, regardless of the context (within marriage or outside of it) in which it is carried out.”
Lastly, see my series of articles on contraception, especially: Contraception and Heresy — Part 2, the use of contraception outside of marriage. The Church has been very clear, in many different magisterial documents, that contraception is gravely immoral, regardless of marital state.
Please take a look at this list of my books and booklets, and see if any topic interests you.