Am I wrong?

My boyfriend has been living with me for 5 years and only pays the monthly power bill (majority his due to the charging of his equipment in the garage - I did a comparison from previous years/months electricity bills before he moved in with me) and contributes when he can to food. I have two children that are not biologically his that live with us. I pay everything else (mortgage, gas, majority of food, insurances etc) so basically all of my wages goes to the bills while he saves his wages to get ahead in his business (he wants to purchase a work van for his employee). Basically I pay around $1100 a week on bills and he pays on average $110 a week. I felt like I was getting resentful so we had a discussion about this and I was blown away with his response of "you had this house and everything else before I moved in so you would have to pay it on your own anyway" explaining that he shouldn't have to pay for 4th of the mortgage etc (I split everything 4 ways so he does not have to pay for my children's share of costs). I can't even use my garage anymore because his car and tools etc are in there and he has taken over it. So I feel like he should be at least contributing more to the household. His reaction was entitled and I then realised it's like an expectation from him that I pay everything. It's given me the huge ICK. I get resentful that he has money to spare and is saving while I don't because I'm paying for majority of bills and he doesn't understand how this is an issue to me. I still do majority of all the household work, he's fixed my car a couple of times as he's mechanically minded- which he says I should be grateful for (but then I could go to a mechanic to get my car fixed if I had spare money to do so, like if he paid his share) What would you do if you were me? Am I being ungrateful? Do I have a right to be resentful and upset?