1. Don’t make any further attempts to discuss this with him. You’ve tried everything you can, and learned it only makes things worse. From now on, your goal has to be simply to survive this situation in as good a shape as possible plus supporting your children as much as you can.
2. You say that, legally, you won’t be able to see your children again if you leave. You’ve probably done this already, but, if not… do do whatever you can to get legal and practical advice to confirm this is the case and to check whether there is any support available, wherever you live or can move to, that would let you take the children and support them without being on the streets. (Although, obviously, you’ll have to get this advice in a way your husband doesn’t find out about.) Is there any support available – emotional and/or practical – for abuse victims where you live?
3. If the above does confirm that leaving with the children really isn’t an option at all, think ahead to their adulthood. If you leave once they’re legally of age, will he have any way of stopping them from staying in contact with you? At least, if you plan for that, you’ll have some hope and some light at the end of the tunnel.
4. Read everything you can about patterns of abuse and also about how to deal with a parent who tries to turn the children against you in a divorce or abusive relationship (as there is a high risk he’ll do that and you need to be forearmed). Even if you can’t leave at this point, reading more and confirming for yourself that it isn’t your fault will be helpful.
5. You mentioned you don’t work. Is this due to his wishes, your health problems, or both? If the former, what would happen if you simply went and got a job anyway? (Obviously the first answer to that would be that he’d be furious, but this is one situation where it would probably be worth dealing with more rages for the sake of the money and independence it would bring you.)