I have a problem with porn

Hi, "Jason" here, I have a problem with porn, I knew I did, but never really was able to quit. I guess it started when I was a kid, maybe 12-13 when I found a Hustler on the side of the street growing up, from then on I've watched it, not regularly, but more than I should have. Fast forward 30 years and now I'm married to the love of my life and it's ruining my marriage. I've tried to quit but it's fucking hard. I was doing good and I haven't watched it in 4-5 days or so, but had a relapse and left the page open on my browser which I forgot about and my wife saw when we were sitting on the cough last night. Now shes mad at me and is not talking to me, thinking I'm not taking this seriously. In the past few months I deleted everything I could find that I saved on my computer and installed a porn blocker on my network last night which seems to work based on some testing I did.
What would be a good next step? I know it's destroying my marriage and effacing me in other ways so I REALLY WANT TO QUIT!