My individual decision process broken into simplistic steps for the sake of this thread
All in hindsight and based on my perceptions only.
1) Get married despite red flags so plentiful and big they nearly blocked out the sun. This was due to unrecognized codependency issues, denial, and selfishness. This - this is where I had the power to do something different, something better, but we can't unwind the clock.
2) Have children. This resulted in a pretty big (and unexpected) shift in how I viewed family, my priorities, and my expectations.
3) Stay married despite things becoming more difficult. Stay married for the children. Belief that two parent family was the only way to raise children even if I need to sacrifice myself. I actually spent hours reading on-line about the devastation of divorce on children so I would solidify my resolve to stay married. I'm Catholic. We are all about sacrifice, guilt, and marriage vows. Codependency issues were again a driving force.
4) I spent 16 years with my ex, married for 11 years. The last three years were spent crying and praying for him to please do something terrible. Please give me permission to leave. (He isn't a terrible person and thank you world for him not doing a terrible thing.) Then I would fantasize about death. Mine or his - didn't much matter. Codependency issues had me drowning. I hit my bottom. I had long ago given up joy and happiness but I could no longer support him, could no longer deny alcoholism, I could no longer get through the days, could no longer be a loving mother. I had given up hope of things ever getting better. I could only see more of the same and worse. I was so exhausted. I could not emotionally separate from him so I really didn't feel my own emotions - I was feeling his. Codependency again and so while alcoholism was the death of this relationship, codependency was the ground it grew in.
5) I had a very clear picture one day that last summer we were together. My ex was mowing the lawn and one of our little boys was following behind him with a toy mower. The dog was running around. It fit perfectly with that picture I had in my head - the fantasy of my life. I turned my head and the other little boy was at the cooler pretending to drink a beer.
I was so stricken with grief at that moment. I did not want any of this for my babies. They deserved more from him and from me. I could not fix him. I decided I had to leave but I needed two more weeks and a very dreadful vacation to get me moving.
6) I left. I left feeling like I was throwing them under the bus to save myself but I was out of options.
7) We did see a counselor but she refused to do marriage counseling until he was in an active recovery program.
So I am now a divorced Catholic woman (which is fine btw as long as I never intend to date while my husband in god's eyes is alive) raising four kids all alone in a single parent home with no family and no friends. That isn't what I wanted for my babies either but sometimes all the choices suck and so we pick the least suckiest of the available options.
So when do we leave and when do we stay? What is the right decision? How much sickness can we withstand? Where are our obligations? Who do we take down with us? We all find our own answers. I think I've made many mistakes when answering those questions and I'm not the only one paying the price.