Leaving......enormous relief or massive regret?

I am finally ready to get off this ADHD merry go round, exhausted and disorientated with life.  My husband has so many great qualities but I cannot cope with the instability of our relationship any longer. It is like having a cross awkward, dopey child one minute and an overexcited child with tunnel vision the next. I never feel I can rely on him to be a husband that I can turn to, for him to take the lead.  He is wonderfully loving to me and my children but has caused us so much pain. Cheating, drugs, alcohol, lying...you name it he's put us through it. Although he is trying his very best to put it all right I have to call it a day almost 3 years after everything was revealed as I am spent.

As much as I want to have empathy for his condition I want some happiness and stability.  Has anyone out there given in and felt enormous relief or massive regret?