sparkles
re your comment that I have separated out for more clarity:-
"I feel like things are always on his terms and usually find myself just agreeing with him for an easy life".
Your whole relationship with him seems to be all on his terms frankly. He has it made with you and treats you disrespectfully as well. He seems to have no real respect for you. And indeed your passive "oh ok then" response to your perfectly reasonable request for he to take his child out was just further proof of that disrespect towards you.
"All in all he is a good dad and partner although he probably doesn’t sound it. There’s just this selfish streak".
Selfish people do not tend to make for being good as people let alone partners either. What makes him a good dad and partner to you; what are your definitions of these words?. His selfishness too holds no bounds. I think too he treats this home as some sort of hotel with attendant maid service i.e. you to service him. How long have you been together?
"He occasionally helps in the house, but lets me know that it isn’t his job".
Oh that is too bad, he is really acting as the Big Man here isn't he?. He lives there too so it is his equal responsibility re the chores and childcare. Do not ever think of what he does too as "help" because he is equally responsible for how the household runs.
"I’m not currently working but currently in the middle of looking for something. I had a baby 6 weeks ago so there’s a few things to consider and work out regarding a job"
Congratulations to you on the birth of your second child
. Put your children and your own self first and foremost in your life going forward. Consider what you want to teach them about relationships and what they are learning here. I don't personally think you want your eldest son to be just like his own father is when he is an adult. Would you want either child as adults to be in a relationship like you are describing, probably not.
How else can you expand your horizons here, only visiting your mother and supermarket seems so limited and that is not your fault (its the times we are living through currently). Can you retrain and learn new skills at college?.