I’m so sorry you are going through this. I went through something similar in June 2019. My husband admitted to a s& porn addiction. We did 3 things that helped a lot- we went to a therapist that specializes in sex addiction and marriages (look for C-SAT credentials) and my stipulation/ boundary for staying was that he enter recovery in a 12 step program called Sexaholics Anonymous, attend phone or in person meetings if possible, every day for 90 days, no excuses. At the time we were living in a bigger city so he could go to a few in person SA meetings, and the rest he calls in to a meeting over the phone. He got a sponsor and he worked the 12 steps. I also worked a 12 step program and that helped me a lot. Your Spouse is telling you the truth when he says it’s worst than he admitted to, but he is lying to you and to himself when he blamed you for being "too vanilla." Sex addiction is a very real, very common addiction that unfortunately is stigmatized in our culture just like alcoholism used to be, but SA’s are people who were raised experiencing trauma (if you stay with him and go to therapy and he goes into recovery for this, you will likely learn a whole lot about his trauma as a child) and this very specific set of circumstances creates this reaction in people. It’s called growing up with Overt, Covert, and Emotional Incest. It is the circumstances that create this addiction. Once the root cause is faced, and the activity that feeds the addiction is stopped, true healing can begin. In the meantime, what you’re experiencing is called C-PTSD. It’s extremely traumatic to go through this, and you will need a safe support system. You will need healing of your own. His excuses for why is a way to escape the blame/ shame he feels for himself, which is adding insult to a terrible injury. The truth is that right now he himself doesn’t know why he does it, and only if he goes in to SA recovery will he find out. But this addiction was there long before he met you, and in a way he is a victim, too, but how things turn out will depend on his willingness to get well and face it.
I told my husband what my firm non negotiable boundaries were, I moved in to the guest room, and did a lot of praying. You can go to 12 step meetings, too, they help so much. There’s CODA, Al Anon, or therapy for yourself through an C-SAT therapist, who often organize support groups. A lot of church’s have support groups for this, too. This is one of the most common addictions in the world, growing more due to the internet and people being exposed at younger ages, and that combined with a certain style of upbringing is what creates this addiction. Take space from his mother while you go through this if you want to see him get well. His mother is likely a big part of the equation. Books to read to learn about sex addiction is anything by Dr. Patrick Carnes.
Keep praying! The third thing that helped me is I found a faith in a Higher Power of my own understanding and leaned hard on that faith, I prayed often, put the whole problem into God’s hands. Today my husband has 5 years sober in SA, there are no secrets between us, we are rebuilding trust, we are in love. We are deeply intimate and we know the worst in each other and the best. It can be a better marriage. I have a dear friend in my same situation who left, and got divorced, she is happy, too. Either way, YOUR future is going to improve if you get healing for yourself. Strong boundaries, and don’t believe his bullshit. Early recovery if he chooses to get sober/ get well in SA is a process of extracting his head from his ***, it takes a while for sanity (empathy for you) to be restored. He will go through an actual physical detox as his body struggles to adapt chemically to less dopamine hits, but then comes freedom and a new joy if he embraces recovery. Don’t let him blame you, it’s not true. It’s an excuse so he doesn’t have to look deeper at his shame, and he will have to face it in recovery. My husband continues to work an SA program, still goes to meetings. He no longer has a wandering eye, he’s happy, he’s the best version of himself. It’s like an alcoholic who stops drinking and goes into AA, they get clean, get well, start to be peaceful and they get free from the pain cycle in addiction. The good news is that he is willing to tell you it’s worse than you know- that’s an indication he wants to get well because addiction is never about pleasure, it’s how it starts looking for relief from pain but at the end stage of addiction it’s no longer fun but compulsive. Whatever he chooses, YOU will know peace and joy again if you focus on your healing journey.