I need some advice in my life

I had a baby two years ago, and decided to go to school to become a nurse. I recently have been accepted into a nursing program and I am looking at three more years of school. In the last two years I have strived to raise a well adjusted child with the help of his father, but the problem is that his father does not seem to want to put our baby first like I do. I am struggling to keep a relationship with him, and I feel like I am falling out of love. I work , go to school and spend my days with our son. He works and has alot of extra time that I feel he takes for granted. I am frustrated too because it seems like he is always thinking about ways to spend money, when I want to save for our future. For example he has been obsessing over a lift for his truck and that will cost $600.00. He tells me that he is sorry that his hobbies are more expensive than mine, but I can't help but think when do I even have time for hobbies. I know I am coming off bitter towards him, but it is the frustration coming out.
This put me over the edge when he said that we needed a dog. I told him no because I know that the responsibility would fall on my shoulders because he has showed me in the past that he doesn't want to put forth the effort to take care of a dog. He says I treat him like he is two, and maybe I do because I feel like I have to be the adult in our relationship. I am 22 years old and and he is 24. We have been together five years. I feel alot older than 22, and a big part of this is because I am a parent, but I shouldn't feel like I have two kids.
So, do you think I am being too hard on him? I talk to my mom, and she tells me that he shouldn't treat me like this and should pull his head out, but I also have to keep in mind that mothers do take there kids side. Am I better off without him? I am trying to do some soul searching:\?

I welcome any advice