I'm sorry to read about your situation, Kittycat- it sounds as if things are really unpleasant at the moment. It must also be a difficult time for your children. Whether the arguments are done around them or not; they will be sensing that mummy & daddy are unhappy.
No one here is going to be able to tell you what you should do. This has to be a decission you make in order to achieve the best outcome to your current situation. Do you think this is something you & your husband are going to be able to work through with talking? Have you tried marriage therapies? If not, would you & your husband consider them? If you think there is something worth saving in your marriage, then talking- with a counsellor- may be the best option. The problem with talking- just you & him- is the lack of control in the emotions & the blame for the failures in the marriage, bouncing back & forth. A counsellor can act as a director, as such. They can make sure you both get a chance to say what you need to, without a ricocheting game of guilt-trips, blame & name-calling.
However, sometimes, time-out and a seperation may be what's needed. Perhaps a bit of space between you & him, yet still spending time every week as a family (to lessen the impact of the situation on your children, yet you can still keep your personal relationship at a distance).
You haven't explicitly mentioned spousal abuse in your post, yet you say he is "demeaning, controlling etc". Would you say he is psychologically or emotionally abusive? Does he resrict your movements, the clothes you wear, friends & activities? Don't worry, I'm not really asking for details, I'm simply confirming what you mean, because I don't want to come accross as too hasty in my advice.
Yet I do believe that if he is emotionally abusive, you need to take a step out of the marriage for a while & develop as a woman & mother. You shouldn't be anyone's emotional punching bag. NO ONE has the right to make you feel inferior & small and NO ONE has the right to control you. A marriage is a two-way street- it's a union of two heads & two hearts and NO ONE should be in control of it.
Often, I think women stay in relationships such as yours, because the world seems a harsh place without that 'special someone' in your life. Children are always a major factor in the decission to split up, but often, parents don't realise that the children are the silent sufferers. They hear the screams & words spat with poison and they feel torn between mummy & daddy. No child wants their parents to be unhappy and sometimes, it's a relief when the split comes. It's difficult at first, but if the parents can be civil and mature about it, they can make it a peaceful transition for their children. However, what's going on- right now- is detrimental to your kids. They probably don't understand why daddy's angry all the time or why mummy's sad- and they have absolutely no control over the situation and they have no idea when there will be peace. There is also the fact that your children will pick up on how your husband treats you & will, eventually, treat you with a similar disregard. Children learn from what is shown to them; our behaviours become their behaviours over time. By standing up and facing the difficulties ahead, you show them strength and a way to take control of their lives.
The world is harsh for all parties involved when parents split up, but it's only harsh for a little while.
Whatever you decide, Kittycat- I hope it works out for the best.