Hi Dorisena,
In response to the question you posed to the Dr., I too asked this question, and eventually, found my own answer.
I believe everyone has their own reasons for staying or leaving.
I was married to someone who was, for lack of a better word, toxic. When he was good, he was very good, and when he was bad, he was horrid. I chose to leave. I would have died in that marriage. I know that now
After leaving, I Worked hard on my own issues and over time, eventually found the love of my life, best friend and companion. So for me it was the best decision I could have made for myself and family. Having sons, it was important to me, that they would be exposed to healthy male figures. (My father was that for them.)
Later, after many years into my new relationship, I was phoned by my ex-husband who had sought help and for years, had a much better life. He called me to ask forgiveness for all the pain he caused me, and told me he regretted not seeking help sooner. He was very honest and explained he had been diagnosed with bipolar disorder, which explained so much about what was going on while married to him. He thanked me for leaving, he said that motivated him to seek help. I was so set free knowing that my actions contributed in some small way, to his recovery. What I didn't know was he was essentially making peace with his past, and saying goodbye. 4 days later he took his own life. I am so glad he found some peace. But he made a permanent decision for a temporary problem. That was in 2010, the economy had tanked and his very successful business was heading for bankruptcy and he was hopeless about ever being able to turn it around. There's more, but my point is, you can't know the future or control the the decisions of others. I made my choice, and I have no regrets. I hope you don't either.