There were unstable phases, particularily between childhood and being a young adult, but even then, with the most extreme things, there were lines I never crossed.
For instance, when my parents divorced and I stayed living with my Mum who more and more turned to alcohol to drown her sorrows. I tried to help her, but I couldn't. My mind went places.. dark places. But I decided to move to my Dad when I felt myself less and less able to withstand my fantasies. Even then, that choice was a conscious one.