My bf/father my children wont stop gambling HELP!!!?

Hi I don't know what to do or where to turn no more or even how to handle the situation. My boyfriend the father of my children wont stop gambling it came to the point where his parents have to budget his money so our bills get paid we both work but he makes more then me because he is full time and I am part time that works only 8 to 10 hrs a week I work less because I have young children that need at least one parent around most of the time and too it saves on day care.. But any way for the last 5 months he spends at least 2 two three checks way on gambling a month and he gets paid every week around 300 to 500 dollars a check so he spends between $800 to $1000 a month at the casino and it doesn't help matters because he works there, I don't know if I can bare to leave him because I believe that our children should have both parents but I don't want them going through this anymore either I have tried to leave him to see what would happen if that would help him stop but nope he still gambled plus he stopped me and sat on the car and said I wasn't leaving him funny I know. I just don't know what to do anymore when he doesn't have money he tries and take mine which now I have to hide money from him just to buy diapers or need it for gas. He is almost never home when he doesn't work he is either sleeping or at the casino, he helps a little with our children and gets mad at our two year old just for wanting his attention which is sad. He doesn't know how to care for our 6month old son. I don't know, He admits that he has a gambling problem but he wont admit that he needs help for it. This is taring us a part he use to be so sweet and kind all the time always helping out and always home he use to be able to budget his own money and still have some left over, but that's not him any more. I don't know please help!!! Only serious answer please..