Actually, in your heart, you already know the answer...
Firstly, if this guy doesn't even contribute a single thing, then why are you still keeping him? for his KKB, meh?
Secondly, to keep or not to keep... ask yourself this question: Are you able to have this child without your husband. If without him you are able to provide financially etc. then why not? If you really think you can't have a child without a husband who doesn't provide, then I suggest you don't bring this child to the world and suffer.
Sorry if I am too blunt, but I've been through worse and seen worse. These are just my honest opinions.