You are indeed very confused.

There is an underlying fallacy that needs to be addressed, and, once it is addressed, everything will become clear.

You view yourself as a guilty party. You ponder whether you are responsible for his using porn. Where does the feeling of guilt derive from? You view porn as something bad, hence the feeling of guilt.

In what way can porn be bad?

Is it a crime?

Well, with crimes, usually there is an element of harm and a presence of a victim or victims. Murder and theft fall into this category.

It is also possible to have a crime that violates a rule - hopefully, a non-arbitrary rule that has been put in place to prevent potential harm to innocent victims. DUI/DWI falls in this category. A driver with BAC (blood alcohol content) above the legal limit can be stopped and arrested even if he/she has not caused an accident. This is because drunk driving CAN cause accidents that would endanger people's lives so there is a justification to arresting people who drive with high BAC. Then, they may plead guilty in court.

There are also crimes that are considered crimes in order to prevent harm to people who cannot stand up for themselves. Statutory rape falls in this category.

Where would porn be?

Clearly, viewing porn is not a violation of any rule. We have rules on the BAC allowed for legal driving, they vary by state and depend on the driver's age, etc., but we have nothing of that sort for viewing porn.

Is there harm to any innocent victim? On the surface, there clearly is none. Porn viewing is a solitary activity in the case of your husband so he cannot possibly harm anybody.

There may be a very very attenuated connection that would attempt to make YOU the victim of his porn viewing. Let me try a hypothetical.

Imagine that sperm were in short supply. I have not found it to be the case in my 42 years - I was raised under socialism and have lived through dairy products being in short supply, boots and shoes being in very short supply, and all sorts of commodities being in short supply, but I have never lived through a shortage of sperm. For the sake of the hypothetical, though, let us imagine that there existed a critical shortage of sperm.

Critical shortages often necessitate wartime-like measures, such as rations.

So let us picture rations of sperm in your household. As his lawful wife, you have the right to the rations. If he spends his sperm on porn, he robs you of your ration, and that act victimizes you. So you are the victim. Very attenuated, but still something.

Further, can porn viewing be akin to statutory rape in that it involves parties unable to give meaningful consent? No, since it involves him, an adult, and the material he views (hopefully, one that was produced using adult actors who were paid for their time and skill or adult amateurs who derived satisfaction from performing for free). The material may be copyrighted so there might be intellectual property issues all the way to criminal intellectual property theft but it is unlikely and I won't go into that at all (plus, you as his wife would never be responsible for his intellectual property violations in any case -- you can only be responsible for the debts he incurs while married to you, but not for violations of copyright or his DUI/DWI and so on and so forth).

Given the above, most likely, porn viewing is not a crime, hence you cannot be responsible.

Or, it is a crime with you as the sole victim. Victims of rape or other forceful violations are not held responsible for their own victimization.

So either way you are not responsible.

Then, porn can be viewed as a neutral activity, rather than a negative activity. His engaging in a neutral activity of his own choosing is in no way your responsibility.

Further, it can be viewed as a positive activity, akin to steady state cardio (I do not believe it would meet the criteria of interval training, which is the best form of cardio, but given the elevated heart rate over a period of more than 10 minutes, it would qualify as steady state cardio). Then, to the extent that you cause his engaging in such a beneficial activity (cause in his mind), you should be rewarded.

So either he leaves you alone or he rewards you - definitely no guilt on your end.

It is a completely mental, cognitive exercise that takes a few paragraphs of writing all in all.