Both.
My husband, who I loved and continue to love, developed severe mental illness. I took my promiste to stand by him "in sickness and in health" and never imagined I would leave him due to illness, but he became abusive to me, and to my children. So, I had to choose, and I chose the kids.
Once we got to the point where I felt like my kids were safe, I felt relief, but also profound sadness.
I am sorry this happened to you.
I had to divorce my XDW because she became an alcoholic and would not help help herself.
It did not happen all at once. Instead, it became a little worse every year and way worse once our kids went to college.