this will destroy me

Hello everyone. Where to start. I've been masturbating dangerously since my early teens, and somehow have managed to avoid serious consequences through luck (mostly) but also cunning. By 'dangerously' I not only mean situations where I might find myself in trouble (ie. masturbating in public), but also because I masturbate to porn on my laptop/tablet/phone at home while family members are present but preoccupied, often in the same room. The odds of being discovered are very high, yet I've avoided detection so far, and I've been doing this now for thirty years!

That's bad enough, but I now find myself masturbating to porn within an hour of having sex with my wife. Not because she doesn't satisfy me, but because I need to masturbate to porn specifically, as well. Even more frightening is that my wife, who was initially opposed and very upset by my porn addiction, is now viewing porn a lot herself, to the degree that I have caught her masturbating on several occasions and found myself openly encouraging her! She has expressed concerns that this is coming between us (her changing sexual preference, and my lifelong addiction) and that is the last thing I want.

I'm very concerned that porn will wreck our marriage of 25 years. But I have no idea what to do. I have tried stopping cold-turkey, and managed without masturbation for six weeks, but then I jerked off in a public toilet and couldn't stop ejaculating. It seemed to go on forever, and the feeling was so intense and pleasurable that I relapsed. I am 48 years old, and I masturbate twice a day minimum. If this doesn't end, then it's only a matter of time before this destroys my life. Any advice would be appreciated. I will lurk the forum and read everything, but I thought it would be polite to join and introduce myself before I begin.

My name is Erik, and I am a university educated professional MWM 48 from Sydney, Australia.