I’m sorry you feel offended by the responses. Most people have tried to make it clear that porn is wrong and you have every right to feel hurt and betrayed.
They are also trying to say that while he is wrong and you have every right to feel hurt and betrayed, there are also things you can do to help heal the relationship.
My parents fought for years because of something my father had done repeatedly. Believe me, he was wrong and my mother had every right to be angry. I can understand that her trust was broken and needed to be restored. Years down the line, though, my dad had quite a turnaround and was sincerely trying to do everything right. My mother, however, responded to his attempts to do the right thing by continuing to hold his past against him and nitpick tiny things he did wrong. It was anything but productive, and my mother was wrong to act that way toward him when he was sincerely trying.
Now, it SEEMS, based on what you posted, that a similar thing is going on here. I can understand giving an ultimatum about going to the group when he was looking at porn. But giving an ultimatum about it when he was posting memes doesn’t sound reasonable. Ultimatums should be reserved for extremely serious instances. What people were trying to say is not that you shouldn’t be hurt or offended by his looking at porn, but rather that it isn’t helpful or productive to be angry at him for things that aren’t reasonable to be angry about.
If he is indeed verbally abusive, that is certainly something that needs to stop. However, I think what others are trying to point out is that if you respond with ultimatums for things that don’t merit them, that will naturally result in him being defensive toward you. It’s human nature. Yes, he is in the wrong about the porn. But in order to heal the relationship, you need to do your part too. That may entail deciding if something he does merits an ultimatum or if it does not.