In some tribes, refusing sexual relations to a marriage partner can result in physical punishment.
From an article in NCR last week:
Dowling said he endorses the “ABCs” of abstinence, being faithful to one partner and living in a committed relationship, but noted that this is only possible in a “regular” or freely chosen partnership. When someone is forced into prostitution in order to eat or when a woman cannot refuse her spouse and transmission of the AIDS virus is likely, the bishop said, she ought to be able to safeguard her life by using a condom and microbicides.
Wearing a condom to protect one’s life or the life of one’s partner is not the same as using it to prevent new life, Dowling said. When used to shield the body from the AIDS virus, a condom is not a contraceptive, he added, and thus does not conflict with traditional church teaching.
Dowling said he is encouraged by support he has received from theologians. The Southern African bishops’ conference remains firmly opposed to their use, but the bishops have “opened the door” a crack in the case of “discordant couples,” he said, allowing a partner to make “an informed choice” if the other partner is infected with the deadly virus.
There might be some applicability of the principle of double effect here: the woman uses the condom to save her life. That is the primary use. The fact that it also serves as a contraceptive is a secondary effect.