Can someone tell me that it gets better?

I'm marrying my partner in about a week. I have faith that he is done with this life. Maybe I'm stupid, but I'm actually not worried about him relapsing in the future. My problem is not worrying about the future, but making peace with the past.

Will I feel like I ever know the full truth about our past? Will I stop feeling like he's hiding more? Will I ever trust him fully? He shattered my understanding of reality.. will that feeling ever go away? Will I ever feel like I fully know him? Will my nervous system heal?

For context, my partner has had a porn addiction for years, and he says he never realized it until he got caught by me 2 months ago. Some porn was okay in our relationship, but he abused and broke that boundary by going on dating apps and messaging apps - which he says was all anonymous and for masturbation only. He just put it all in a box and closed the box during our normal everyday life. He compartmentalized and pushed things down so far that he said it never felt like he was even hiding something from me. Can this be true like on a psychological level?

He was 100 percent the best partner before I found this out and I was so happy to be marrying him. I looked at him like he hung the moon and stars. Now I wonder if I ever knew him at all. Is he still a good person and the person that I loved? Can we get through this, and can I make peace with the fact that our past 7-year relationship involved a secret that I was never in on? Will I forgive him for what he's done and for putting a cloud over what is supposed to be the happiest time of my life?