It is quite a stretch to start out with a married couple, and then all of a sudden she is supposed to kill him in self defense!
If she is married to him, why would it be rape? If this was an arranged marriage, that is not all that uncommon in some countries.
I believe that there is also a problem in Africa where unmarried twelve-year-old girls get pregnant all of the time, and then they are shunned, but that is another subject.
It is simply a different culture than what we’re used to. If this woman left her husband, maybe she would be beaten or killed.
Since the Church forbids condoms, there is just no good answer here. She can’t abstain if her husband refuses to abstain. He will probably chase her and tease her until she gives in.
I guess her only choice is to get the disease. Sad, but true.