Wasn't being flippant, I posted before your second post.
My first thought is, what a complete and utter bastard. Do you have friends and family nearby to rally?
You need to make a CSA claim and start looking at tax credits you can claim. CAB can help you here. Or go to entitledto.com for some guide.
Whose name is the house/tenancy in? You must been terrible but you can get some control over what is happening here. Make an appointment to see a solicitor pronto.
How long have you been married?
I doubt he will want no contact with the children. But if he really doesn't then you are much better off without such a loser anyway. He sounds an utterly selfish, immature idiot.
Hang in there. More will be along to support you soon. Keep posting and remember you have the most precious things in the world - your lovely children.