I can't tell you when is the right time, or what is the right thing to do. I have been struggling with these issues for years and have put a few agonised threads on here in recent weeks.
I am about to start another, I am going to get out and I need to find the strength to do it, and help with practicalities. It's terrifying, but I think my dcs need a happy mum more than they need their parents under one roof. It's such a tough call, I have been unhappy for so so long.
Not hijacking, all I will say is that my experience has been that it takes a long time to reach the point. I have thought I'd got there more than once, but have backed down in the face of bullying and emotional blackmail. If things carry on as they are, all you can do is try and change them. When you get to the point where you feel you have exhausted the possibilities you at the end of the road. I feel I am in this place, you sound like me a two years, a year, a few months ago. I have tried and tried. It's broken and can't be fixed. I have suffered so many agonies over this. But I've reached the point where I feel I can hardly bear another 24 hours with this person.
Everyone I know who chose to split with dh got to this point. Fact is, women will try and try, no one wants a marriage to end, and it's mourning all the hopes and dreams you had as well.
I feel for you and hope you will find a way to resolve your situation. x