Toofattorun My DH and I faced a similar issue approximately 2 years into what is now a 10 year relationship, maybe what we went through will help you in some way. I regularly found porn stashes and stumbled across web browsing history and would say 'I don't like that you have this/watched that' repeatedly until I reached breaking point. At first he'd say it was his mates or whatever (we were young) but eventually, when it was just to two of us and there was no-one to blame he (belligerently) admitted it. We had a huge row, and I moved out. After I'd moved out, and calmed down, I re-assessed what I wanted. I could have left it at that, but I knew I still loved him so we got together and made a plan.
We no longer argue when someone is mad. We have some time apart (he might go to gym) and we reconvene when we are both calm.
I am honest. Mostly this means with myself. Its too easy to say 'you always do...' or 'you never....' but if I am really honest, those things aren't strictly true. In my case it was 'you always watch porn instead of coming to bed with me', but when I explained calmly that's how I felt, he agreed, and said it was easier to wait till I was asleep, do his thing and come to bed, than to attempt to come on to me when I clearly wasn't interested. So we'd both thought the other didn't want sex, when we both actually did! Or, more truthfully I often think I can't be bothered but then love it when we get going (tmi- sorry!)
In the end, it prompted further discussion, and he told me he was unhappy that I had gained so much weight (size 8 to a size 14) but he loved me so much he didn't want to hurt me, but did feel less aroused by me than he used to. The whole discussion brought us closer, made me realise how much more he has going on in his brain than I gave him credit for and we understand each other better. Men are very simple often in their response to a situation, so it may be a complex set of emotions that he doesn't necessarily understand all of that has led to this very primal response.
Further to our discussion, we both agreed that we did not like the porn industry and went about looking for a more ethical alternative that we could enjoy together - as it happened we never needed to.
Good luck with this conversation, but bear in mind although your feelings may be hurt, he may also be feeling ashamed, or a range of other feelings so try to remain calm and non-accusatory.