My husband has basically made me a single mother. I want to leave him.

My husband (27M) and I (26F) are both in the same career field. We?ve been married for 2 years, together for almost 8 total. I just had a baby 7 weeks ago.
Last year, my husband tried out for a specific unit and ended up quitting during the process. It was very unexpected from him. He wanted to try again this year. The school to get into the unit is very gruesome and is long hours. He basically expected his family and my family to help with the baby until the school was over. I should also mention that the unit is also very busy. I also work full time.
The first week of his school is over. My family cannot help me every single day of the week since they all have jobs. His mother has offered to help but she is practically useless. She just wants to hold the baby all day and doesn?t want to help with any other chores. She?s essentially a pack and play.
After the first week, I asked my husband if he could take a night feed so I could sleep. He said absolutely.
It is the night before the 2nd week of his school. I asked if he?d be able to help with a night feed tonight. He said ?I don?t think it?s possible for me to help overnight while I?m in the school.? So now I feel lied to. By the way, he?s going to get a straight 8 hours of sleep tonight.
There have been nights I have only slept 2 hours and I am delirious. I have called my mother crying begging for her help. I am at a loss, I cannot believe my husband won?t sacrifice an hour of his sleep to help with our newborn baby, our first baby also.
This (on top of his general selfishness and being unappreciative) has made me want to separate from him. At least for a while, until we can decide to try to work something out or just divorce.
Am I overreacting? What steps should I take to separate from him if this is what I want to do? Should I take a few days to really think this over? I don?t want my son to grow up in a broken family but I am really heartbroken and miserable.
TLDR; my husband won?t help with our baby overnight because of a training he?s doing for his career, even though he said he would. It has made me realize he will be selfish for the rest of our marriage. I want to leave him but don?t know if I am overreacting.
Edit: I should clarify, my husband didn?t quit his job. There?s a specific training through our career for a specialized unit. It?s sort of like SWAT/Bootcamp training. He quit that last year. He trained until this year and is now further in the process than last year. The days are long, probably average 15 hour days 6 days a week. But he did tell me that the 2nd week is supposed to be around 10-12 hours and he would help with night feeds. Now that we are at the first day of the second week, he?s back tracking because he?s ?worried? it?ll be longer than 10 hours.
My comment below: Thank you everyone for your kind words and advice. It is really helpful. I do realize that I am really sleep deprived. I know the old saying ?don?t make any rash decisions, like divorce, within the first year of having a kid?. I?m trying my best to stick by him but this selfishness is a pattern I?ve ignored for far too long. His parents did everything for him and he was extremely spoiled. He?s made to believe he?s the greatest person that has graced the earth. It?s also my fault for continuing to baby him for so long. I just loved making him happy and taking care of him, even if he didn?t always return the favor. Now that I am going through the hardest thing I?ve ever done, I really could have used his support. I understand this training is also the hardest thing he?s ever done and this job is his dream, but we both made this baby together. He knew the sacrifices he needed to make. What really bothers me is when his solution is ?you need to ask my mom to come during the night, she?s offered and you?re not taking her help.? My MIL has made comments about falling asleep with the baby in bed and how ?your body won?t allow you to roll on him so it?s perfectly safe?. She has also suggested leaving him in his swing while we take a nap? which is extremely dangerous. She does not help with any chores when she comes over, she just holds the baby for hours. She has offered to be the ?night nurse? but honestly, I don?t trust her and I?m scared she?ll accidentally harm my baby. My mother on the other hand has been a godsend. She is here within minutes to help and she makes sure to do as many chores for me as possible BEFORE she even attempts to hold the baby. However, she is a teacher full time and isn?t available to help me.
I told my husband that this is going to lead to a divorce. It?s funny how that changed his mentality and now he ?never said he wouldn?t take a night feed? and is running around trying to help as much as he can before he has to sleep. He has to get up at 3am. I would be fine with him helping out but I don?t feel I can rely on him. He will be willing to help for a day or so, then he will be too tired and telling me that he?s failing the school because he?s too tired. He also tends to shape up for a week and then reverts back to old habits. So I think this is just the last straw for me.


Source.