To be frank, this really does depend on the norms of the society, and that also applies in the case of Mary. That's because the norms of society are what people are going to apply when the information about the case comes out.

If we are using a model like presented in Molyneux's Practical Anarchy, then the social norm could be that people would be expected to carry some kind of certification of health from a trusted authority. When Marv gets tested for HIV and it comes back positive, that authority would take away his certification, or at least update it to be HIV+ (after all, HIV+ people do date, but they may not jump in bed with someone else who also has hepititus, etc). A person might say that it would be up to the woman to inquire about this certification and it would be up to Marv to be truthful about that inquiry. Thus a person could have the view that if a man or woman is too interested in sex to inquire about the health certification.

One thing that is important, though, is that in a voluntary society, the people around you define the response. So if the people in Marv's town agree that the women should have been more cautious, then they would continue to trade with him. If, however, they do feel he should have been more forthcoming with the information, they may just decide to not trade with him, making it so that he would have to self sustain or move to an area that does accept what he did. Almost certainly, people who know and are friends with this woman would be unlikely to trade with Marv and may also decide to not trade with people known to associate with Marv, which could be limiting to his life.

I bring this up because it seems like people have this impression of creating a black and white test for NAP violation, and then applying that to determine a person's status in the society, but because everything is voluntary, there is no exact answer to these questions.