I really do know what this feels like. A long time ago my (almost) husband was caught getting his jollies off in a similar way. Transpired he had done the same to the wife before and eventually it led to cheating - which he convinced me at the time was her fault for being so cold. He actually got me to feel sorry for him.
I let those small things slide. I think I caught him watching porn one night when I was really ill and asking for a cuddle because I'd been alone all day. He;d said he was "working". I think I found him on some questionable sites when I was at a funeral of a beloved aunt.
Those kind of things aren't just "looking at porn". They show something a bit more sinister in the character.
I really loved my ex, very deeply loved him and he was a wonderful partner but he had this side of him where he was devious and capable of lying and also enjoyed sex online with other people.
I turned a blind eye to the one or two tiny occasions stuff like this came up because 99% he was the man of my dreams and there wasn't anything he;d not do for me. even now men struggle to live up to what an amazing partner this guy was. He sure knew what he was doing!!!!
I won't type the story but he left me during a hard time in my life (illness, job loss, family problems) because he was juts too selfish to support me through it when I wasn't "fun" anymore.
He was selfish through and through, and my value was seen by him in terms of how good I made him feel. When I was in a rough patch it never occurred to him to stand by me till I got out of the tunnel. I just got a text message to say it was over and he;d moved out. After 6 years. That was all the coward could offer.
That same selfishness is what makes them able to wank off to people on the internet. They can compartmentalise, they can do whatever is best for THEM with little concern for others feelings and they are very selfish.
While you are newlyweds believe me...it is easy for him to be a "good husband" and show you love WHILE HE WANTS TO.
Fast forward 10 or 20 years to the young secretary flirting with him, or then time you get a serious illness or to financial problems or things with the kids...believe me...the second HE stops wanting you, NEEDING you...he will be gone -because people like that deep down don't give a fuck about other people the way you or I do. They are missing something in their head, and believe me, when they leave you they try and destroy you on their wy out to feel less guilty and try and make you feel like it was your fault.
What he's done is sick in the head.
I'd leave him, but I know that is easier said than done when you are married. If you can;t leave him, I would insist he sees a counsellor. Believe me, like my ex he probably has very deep psychological issues he needs help with. I doubt he will go though. If he won't, then please....YOU GO.
I wished so hard that I had known at the time that people who love you truly don't do these things. It's so simple, and yet so hard to see when you are in it. Read your OP and ask yourself if this is what you wanted as a newlywed. Please think of what you deserve
xxxxxd