It was certainly a contributing factor in my marital problems. My H WAS neglecting me. We already had an SSM, with HIM as the low drive spouse, and it was much more "convenient" to do porn--I think he did it mostly out of habit--than is was to take time for the wife.
I was sick about it, but too naive to take firm action and lay down a boundary. I just assumed he didn't want to ML because he just didn't love me all that much. I also assumed that the women in the pictures he got off to were more exciting and that I must be too plain and boring. (I'm not...far from it, BTW)
For me, it was cheating...just as painful as an affair would have been. You see, he was "giving away" my LL--physical touch. Just food for thought. Porn is NOT innocent.