Husband's porn addiction?

I'm new here so I'm doing this anonymously... I recently learned of my husband's porn addiction. We'll have been married 4 years in September. We've removed temptation in the home. I've put parental blocks on his devices and am monitoring his activity- by his request, so I'm not just being overbearing. He asked for my help with getting away from this habit. There were many lies leading up to my discovering this by way of credit card statements... My struggle is, how do we rebuild trust after this coming out? I never expected this from my husband but here we are and I'm stumped. Please help.