I do think he is obsessed with this type or porn.In every day life he does shopping, cooking, we each do bedtime for the 2 kids,we talk and enjoy each others company.It is really when it comes to sex he acts like this. But it's getting enough for me to stop the relationship. I read here day after day about women in these situations, about how women are threated, and I don't think it's acceptable just because it only happens in the moment of sex.
No, it's not acceptable, I think the question if he is otherwise a good man is it something that can change?
I don't know how well you guys communicate in your relationship, but it's pretty common for couples to have poor communication on some issues, where somehow the real questions and concerns aren't getting through to the other person. Sex is difficult to talk about for a lot of people, and we also bring a lot of preconceptions to our sexual relationships that often don't ever get discussed.
I think it might be really worthwhile for him to look at some of those anti-porn writings by men, but it might also be difficult to see himself that way. But to ask him how he would feel if you were pressuring him for anal sex, or to talk about the medical side of it, not as an accusation but as part of a real conversation, might be effective. I would emphasis that ignoring what you've clearly said you aren't interested is a real warning sign and game changer for you, it shows he is not behaving in a way that is normal for a caring person. People find it difficult to see themselves that way, or as addicted, it's emotionally painful and they feel like they are normal, but that might hit home, that his behaviour has become clearly abnormal.
I also think your idea of a porn hiatus would be a very good thing, to see how it changes his feelings. He might find some use in looking at the effects of porn watching on sexual response, there have been some good articles on this. The unfortunate fact is that porn has become so ubiquitous, and so normalised for many, that a lot of people have never seen it seriously questioned in their peer group. They are like people who come from a family or community of problem drinkers who think their behaviour is completely normal.
None of this may work, but on the other hand, it may. People have come to see their problem around these issues and changed, and that would be the best outcome really. If it doesn't, then it may become quite clear what you want or need to do.