Someone who, knowing they have an STD (usually HIV), does not disclose this to another and has unprotected sex with them, has not obtained informed consent.
If your consent to sleep with your spouse is contingent upon their fidelity, have they committed sexual assault by not disclosing affairs?
No because the consent is between the two people engaged in the act.
Does the health aspect become significant, or even determinative, if the potential health consequences are cited as the reason consent is vitiated in the event of "risk" affairs?
No because the court doesn't act on suspicion but makes determinations on cogent and relevant evidence not ones fears and/or anxieties and/or worries about something happening. The court generally only orders on matters for which evidence to the fact has been established. Courts do not move on speculation generally...
Does it matter if the spouse believes they are clean, or that their affairs will not have negative health consequences?
No. Because the fact that someone has an affair is not clinically proven to cause a negative health consequence on the other non-involved party. This is where accute care and mental health differ quite significantly.
If this was the case everyone would be bringing claims of all sorts... For example, if I honk my horn at someone and they have a mental health breakdown am I responsible?
CAMH is not filled with people who have been the "victim" of an extramarital affair.
Also, I caution you on the use of the terminology "negative health consequences". This is only used in the context of determining subjective factors in a clinical encounter and is speculative for informational purposes. A diagnosis cannot be based on "consequences" as they are subjective observations not objective.
I am speaking purely from a ontology basis. Consequences are not "findings"... Vastly different in the context of establishing the "health and well being" of a patient.
While unlikely to see criminal prosecution, could this be battery under the law of torts?
Establishing the evidence that the person in question was aware that they had contracted HIV is the challenge really. You could bring a claim but, establishing the evidence is going to be difficult. (You can bring any claim if you want to court... Even a claim for ONE TRILLION BILLION DOLLARS!)
You have PHIPA to contend with, the privacy of the other party's health information etc... The civil court doesn't willy nilly hand over medical records on request. Incredible grounds has to be made for a court to order the medical records.
With the recent updates in legislation (in Ontario) to PHIPA it closes the door even more on accessibility of the medical information that would be necessary to establish when the person in question tested HIV positive and was notified (and understood) the results of the testing.
Most HIV testing is done through community clinics. The tests are de-identified. So, even if you did get an order allowing for the access to the medical records, good luck finding the matching lab result to the person in question.
If you are successful in establishing a date prior to the encounter that may have transferred HIV through evidence the next challenge in the tort would be establishing malice... That the person intended to transfer the infection to the other party. Which is a whole different ball of wax to deal with.
Medical information is protected... We don't make people publicly identify themselves as HIV positive. The laws allowing people who are HIV positive to mask their medical records was put in place for a reason... Just like we don't make diabetics, people with cancer, and people with other health conditions identify themselves.
Good Luck!
Tayken