My DB and going outside my marriage

I (HLM-40) and wife (LLF-42) had been in a DB for many years. It wasn't just a simple lack of sex but also my situation never had her "knocking on my door" so it was very one sided on me always initiating. The past two years were completely sexless and prior to that for several years it was maybe a handful of times per year. I had attempted to raise this with her on several occasions over the past 3 years, again I seemed to be the only one with concern about this sexless marriage as we would have some dialogue, nothing changed, months would pass as I grew frustrated and would finally raise it again... Finally early last year I told her I was done living in a DB pretending marriage and was going outside the marriage for an intimate relationship. I specifically said I was not asking permission and she could respond however she needed but I was done with status quo and moving on with that aspect of life. She never responded good, bad or otherwise. Come July she confronts me about having a relationship, I said yes thats exactly what I said was going to happen, recall the looong conversation from earlier this year. Since then we have, finally been having proper dialogue about our marriage, how we got to where we are and how we proceed with dissolving it (we are 20 years married with 2 tween kids). I am not alone with the DB crowd in knowing how difficult and hurtful it is to live in pretend marriages without intimacy. My wife has expressed how hurt she is by my actions, yet she doesn't seem to understand the agony and hurtfulness that DBs bring while living in them. My actions are certainly not how everyone would proceed in my scenario, but I am prepared to live and deal with the consequences.