The starting point for me is that the vast majority of men, and a significant portion of women, watch porn. Watching porn is fairly normal behaviour, especially in men.
Obviously 'everyone does it' does not mean it's automatically okay. As you say, porn is often very exploitative.
But porn is not the only mainstream industry that is very exploitative. A lot of retail industries are pretty awful when it comes to child labour and sweat shop work, as well as a wealth of other unsavoury practices. The obvious example is cheap clothing retailers like Primark, but they're far from the only culprit. If your main issue with porn is that it's exploitative, do you always make sure that other products you consume are ethically-sourced? If not, I think there's a degree of hypocrisy.
I would add, however, that porn can have a very damaging affect on its viewers and their relationships (in much the same way that consuming alcohol can be). Some people will be affected fairly minimally, but it can absolutely cause problems in people's sex lives. I'm not sure if that's happened in your relationship at all.
For me, based on your posts, the biggest issue is that your husband appears to have blamed you for him watching porn (but that depends on what was actually said, whether he specifically blamed you or said that he was watching it because of a lack of sex at the moment).
It's really up to you how you feel. What I've tried to do above is put it in perspective, so far as I see it, but obviously you are perfectly entitled to your own views and feelings.