Actually, come to think of it, I believe I recall reading an article written by one of the apologists on this site that NFP is a viable option in this kind of situation.
But you can’t use NFP while on hormonal contraception, that’s the point. It’s not possible.
NFP is predicated upon a woman ovulating. The signs and symptoms that are tracked in order for NFP to work aren’t there unless she is ovulating. When one is on oral hormonal contraception, you generally never ovulate, and if you do, it’s a very rare thing indeed, and quite unpredictable.
Cervical mucus buildup/fadeoff? Won’t happen unless she’s ovulating.
Temperature shift post-ovulation? Won’t happen unless she’s ovulating.
Luteinizing hormone/estrogen surges detectable in urine? Won’t happen unless she’s ovulating.
Saliva ferning in the presence of ovulation hormones? Won’t happen unless she’s ovulating.
Post-ovulatory increase in progesterone in the blood, detectable via blood test? Won’t happen unless she’s ovulating.
How on earth is one supposed to track non-existent symptoms?
OP, hormonal contraception may be the best way to deal with your medical problems. On the other hand, there may be other, equally effective ways. The best way to determine what will work most effectively with your body and conditions is to speak with a doctor (I do second the suggestion of at least contacting a NaPro doctor, as they are trained in more precise hormonal regulation than most OBGYNs) about it.
And to answer your original question: you may use hormonal contraception for the specific purpose of treating a medical condition and still have sex with your husband. See Humanae Vitae, the encyclical on such matters written by Pope Paul VI:
["Lawful Therapeutic Means
- On the other hand, the Church does not consider at all illicit the use of those therapeutic means necessary to cure bodily diseases, even if a foreseeable impediment to procreation should result there from—provided such impediment is not directly intended for any motive whatsoever."](Humanae Vitae (July 25, 1968) | Paul VI)