I gotta speak up about one of the rules you laid out for cheating. If you entered into a monogamous relationship with your significant other, then you should remain monogamous; you cannot cheat on them if they get cancer or in a car wreck and can't have sex anymore. Moreover, physical inability to fuck is not a good reason to leave them either. Someone who is too sick to fuck needs your support more than ever. Anyone who enters into a monogamous relationship should know that it is quite possible that either they or their partner could be randomly struck by an ailment that prevents sex, but this fact alone does not permit them to cheat or leave. It is selfish to cheat on someone in a circumstance such as this. If you really feel the need to cheat on your dying husband or wife, you should have thought about that before you got married.
I Have Two Buttholes
My response after the jump...
I described cheating on a sick or disabled partner—a very seriously ill partner, a profoundly, incapacitatingly disabled partner—like this...
Cheating is permissible when it amounts to the least worst option, i.e. when someone who made a monogamous commitment isn't getting any at home (sick or disabled or withholding-without-cause spouse) and divorce isn't an option (sick or disabled or withholding-without-cause-spouse-who-can't-be-divorced-for-some-karma-imperilling-reason-or-other) and the sex on the side makes it possible for the cheater to stay married and stay sane.
When someone with a sick or disabled partner faces a choice between cheating, leaving, or going insane, I think they should cheat.
But, hey, I agree that people who make monogamous commitments should do their level best to honor those commitments. But an illness or a serious disability can change roles and expectations, IHTB, and tragic and/or hopeless circumstances can quickly transform a lovers-and-partners relationship into patient-and-caretaker relationship. No one suffers more than the sick or disabled person, of course, but the caretaker role places tremendous pressures on the able partner.
If a little discreet cheating makes it possible for someone to be there for a sick or disabled partner—if it makes it possible for that person to remain faithful in the most meaningful sense of the term—no one outside that relationship has a right to judge. And, again, I'm not saying that people in monogamous relationships have a right to cheat on their partners at the first sign of sniffles or if their partners are bedridden for a few months with a broken leg. I'm talking about the grind of years and years of caring for a sick or dying partner.
Circumstances change, IHTB, and sometimes allowances have to made. It's neither helpful nor realistic to demand that others go without physical intimacy for years or decades because you can't wrap your head around a situation where a person might need to sneak out and do a small wrong in order to stay put and do a much larger right.