Ok, first you need to think hard about what you want to do, regardless of his feelings. It sounds like he is confused or too weak to end the relationship, or scared of coping on his own. You may also feel this way. You have to be brutally honest with yourself though. Do you want to break away or not? It sounds like you are deeply unhappy and stressed out in this marriage. It would be a massive move to leave him but you may be happier in the long run, unless you can rekindle things and make each other happy again. If you think this is possible then talk, talk, talk! You must communicate with each other about this, not after a row but when things have been calm for a few days. Be open and honest with each other. But know what you want to say before you say it. This is crunch time for you. Take relationship advice or counselling/therapy first if you think you might benefit. Ultimately only the two of you can sort this out. It sounds like you will be the one to finish it if he is too confused or unable to do it. Put your happiness first and think how it will affect the children, but bear in mind they might be happier if you are living apart and not arguing anymore. A destructive / negative marriage can do more harm to them than a separation.
Hope you sort things out. Good luck.
William.