17. Responsible men can ... first consider how easily this course of action could open wide the way for marital infidelity and a general lowering of moral standards. ... [A] man who grows accustomed to the use of contraceptive methods may forget the reverence due to a woman, and, disregarding her physical and emotional equilibrium, reduce her to being a mere instrument for the satisfaction of his own desires, no longer considering her as his partner whom he should surround with care and affection.
https://www.vatican.va/content/paul-vi/en/encyclicals/docume...
Consequences of Artificial Methods
17. Responsible men can ... first consider how easily this course of action could open wide the way for marital infidelity and a general lowering of moral standards. ... [A] man who grows accustomed to the use of contraceptive methods may forget the reverence due to a woman, and, disregarding her physical and emotional equilibrium, reduce her to being a mere instrument for the satisfaction of his own desires, no longer considering her as his partner whom he should surround with care and affection.