Sadly i must agree with Father Chuck.
What you need to do is get some money together and be prepared to take a stand and stay with that stand.
Take your kids and i am unsure how old your kids are but you tell them as much of the truth as you can that they will understand.
You let them know that Daddy is dealing with some issues and hopefully in time he will get them under control and will come back and be healthy again and be there in your lives again. Let them know that he loves them but that he really needs to stay a way a bit and get better.
You leave him a note that You love him but you no longer like who has become. Let him know that the threats of killing himself are not going to work because in all honesty he has been killing himself all this time and that you already know that eventually at the rate he is going well he will be dead. Let him know you are sick of living this life You are sick of explaining to the kids why Daddy is not there and that you are tired of living a life with him addicted and that until he gets help and gets some clean time (MONTHS) under his belt you will NOT be seeing him.
As far as help that is not too costly Thankfully Crack is not like heroin and so he has no serious withdrawals that are physical except maybe some diarrhea and lack of appetite. So all he needs to do is find some groups and find the WILL in him to want to quit and possibly some good therapy.
Are you in the states? if so most Health departments offer drug treatment on a sliding scale meaning it goes by your income. if he has none than he will not need to pay anything
IF he is not working and you are and you two live together they will if you are married come to you for the money.
He can get help all he has to do is want it and reach for it.
believe me i know crack is a heck of a drug to kick but it can be kicked and there will be times when he will crave and possibly relapse the 3rd month the 6th month are both real tough times
Also he needs to cut all times with anyone who got high with him or who sold it to him.
Most important though is you stick with your choice and do NOT give in.
You can not continue with your life like this your kids are important.
I am by the way speaking from the stand point of a recovering addict. i lost my man because i did not care enough to get clean until it was too late. I really kicked my own butt for that for years. But I am clean and am Glad that i am clean now. It took me a couple tries but i finally go it as i said though there is help out there for folks with limited funds Not a lot but there are some.
Stay strong this may be the thing that helps push him to get help or sadly it may not but it will need to be done because in all honesty he is not going to change if he does not hit his bottom. Losing his family can in fact be the bottom he needs to see he is messing up badly.