Need some advice

I am almost 30 weeks pregnant. The father is my on again off again boyfriend that I've been seeing since high school (I'm 24). He has never been very responsible or good with money. He is also a compulsive liar. I never wanted a long term relationship with him for those reasons, but when I got pregnant I got kind of forced into it. I am student teaching this semester and it was honestly just so much easier for him to live with me. It was extra money (since I'm only working about 8 paid hours/week) and just extra help in general. It was going pretty well for awhile, but lately it's been hard. I haven't seen any money from him for our bills in the last two weeks and he has lied about being paid. He has also been smoking pot in my apartment. I caught him a little over a week ago and now I keep smelling it, but he says it's not him. I obviously don't trust him because he lies so often. I don't know what I'm wanting from this post, I just really need to talk. Am I expecting him to grow up to fast? Should I have ever expected him to man up in the first place? Do I deal with it or get out of it before baby girl gets here?