Snowkitten, when you say "i really do feel that my situation is different" you are right, it is different. You really are not the same as other wives who leave their destructive partners. But the thing is that they aren't the same as each other, either.
Dump your preconceptions about who these other women are and what their circumstances are - these preconceptions stop you from recognising your own problems.
Whether your dh should take "blame" for his actions or not is also a bit of a red herring.
If you just look at the facts, his behaviour is having very adverse effects on you and the kids and you are no longer the happy person you once were. You live for the peaceful days and hope each time it is peaceful again that that there will only be peaceful days in the future and that things will right themselves somehow.
You recognise that the only person who can make a positive change to the situation is you but it seems overwhelming, and I think you are still also in some disbelief that your situation is as it is, clearly it is not something you ever imagined would or even perhaps could happen to you in your life. Feeling overwhelmed is not suprising but Nina is spot on with her "baby steps" approach. I would also suggest that you contact Womens Aid for practical support and advice. You can make a plan, break it down into stages and work through it.
If you are still somewhat undecided about things, just speak to Womens Aid and see what you think about what they say, you have nothing to lose. Speaking to them isn't a firm committment to anything at all. In awful situations from my own experience it can take a while to really properly see what is happening and it is valuable to ask others who are not involved how they see things. For me, a lot of different people told me the same thing - I was being bullied. I couldn't see it and I thought they were sweet and well meaning but that it wasn't bullying because I wasn't a person that could happen to. Eventually, so many people who I respected said the same thing and I realised they were all spot on. Only once I had recognised what the issue truly was could I move on and deal with it. Things were bloody hard but once I had recognised the nature of the problem and decided to fight back I was immediately in a far better place mentally again.
I suspect you do not feel better because you have not yet truly seen and acknowledged what is happening to you. If you do nothing else, talk to some real life people about this and maybe read some literature.
The people who have answered your thread are not looking to sensationalise or exagerate for some drama in their own lives, they are mainly people who have been through difficulties themselves, and wish to offer help. Don't dismiss us as kind but ignorant of your reality - I did that.
Looking in from the outside can often give you clearer vision that looking from the inside out.
Everything really will be OK once you make the changes you need to make. Happy snowkitten is not far away.