Good advice from others above. I think IC/MC will go a long way in helping you two understand and work through these issues. From the outside, your situation seems so far from a desperate point of divorce, but I appreciate that it's hard to not consider that. Have you considered that maybe the reason you brought up divorce is because you feel shame, and also weakness within that shame, and that helplessness makes you want to do a desperate but probably irrational thing? What your wife probably wants/needs right now is to: 1) decide, and 2) begin making small baby steps toward that change.
Take a step back, meditate, remove yourself from the equation, listen to yourself for a second.
I'll comment on the SAA advice. I was a serial cheater, a lot of porn, and really just kind of stuck in using sex to compensate for my own sadness and lack of self-worth. Seeing that I was used to seeking sex/porn, etc. for happiness, I also went to SAA. If there is a real addiction, then it works for many people. However, most addictions have underlying reasons. I quickly learned in therapy/IC that the real issue with emotional disconnection, a lack of self-love, a lack of authenticity with my spouse, in general a disconnect with emotions and emotional expression.
Once I addressed those issues, I never looked at porn again. I did however start dating other women (after being separated with intent to divorce) and definitely learned another very important lesson. Sex will never fulfill you if it is not coupled with true, emotional connection. Further, true emotional connection isn't possible without self-knowledge, self-love, authenticity, and radical honestly. Period.
In other words, you might just find that diving deep into your own personal issues will re-create the way you think about relationship, desire, those needs. And when it does, you'll get that satisfaction in other ways.
I'm only writing this because I think addiction to porn/casual sex is very much a disconnect form self. That said, real addiction should not be underestimated; it must be dealt with.
I really hope you see the opportunity to evolve here. Take a step forward my friend.