Marriage troubles

Lately my husband has been slipping into his old ways. I am 20 weeks pregnant and when we decided to get pregnant we had been doing great for a year. He had actually been being very mature and proved himself to me that he could handle a lot more responsibility. Ever since getting pregnant, he has been slacking on everything. Household chores, saving money for our baby and the appointments and ultrasounds we've been having to pay for because our insurance is crap, and setting up the nursery, and even paying our bills on time. Right now we have $50 to our name. $500+ in medical bills and we don't even pay rent. We both work full time and still can't seem to stay on our feet because of his spending habits. I haven't had a haircut in over a year because I feel bad for spending $40 on myself. Meanwhile he has gotten 20 pairs of shoes in the past 6 months. I've threatened to cut up his card so he can't use it whenever he wants anymore. Or just simply separating our money because I can't trust him anymore. I see now that I will probably be raising our son on my own since he can't even do the most simplest things for a dog. I have been taking care of our dog and feeding it and bathing him and walking him. I don't mind, but if he whines about doing things for a dog, he will whine about doing things for our child. He was the one that came up with the idea to get pregnant in the first place. I wanted to also but I wanted to wait too. He didn't want to, but I think he is bored of the idea since the baby isn't here yet. I'm just scared I am left to handle all of these responsibilities on my own and I can't handle it, I need him to take some of the weight off of my shoulders. Do you think he will change once our kid Is here? Or if he's being this way now, he won't be different after?