Help. Please. 😫

So, a little information about the people involved. My boyfriend and I have been together 2 years now(3 in November). A while back we moved in with his mother and 17 year old brother. I'm not going in major detail about the living situation, but you will notice mentions of it through the story that might help paint the picture. We got stuck and were in need of a place to stay. It ended up working out I guess because right after we started getting it together, his mom is now left unable to bring in money at all. So... Here's my problem. I do not work currently, my boyfriend preferred it that way(longer story). Even though I do stay home, when he is up I am up, and I normally go to bed when he does, but I am up ALL DAY we have a dog and more recently a kitten that has to be bottle fed. In addition, I do all of our laundry, I clean twice a day, my dog is bathed twice a week at least, I clean our vehicles. Basically I take care of everything at home by myself. Which is fine because I am super OCD and I like everything in order and clean constantly, anyways. Slowly but surely I have been coming across things having to do with my SO's mother that are really getting to me. What most recently set it off was that my boyfriend gave her money for groceries, and guess who takes her because she has no vehicle? Yup. No problem. What is a problem is when I took her and his brother to the store, guess what they purchased ? A headset for his brothers Xbox and Mcdonalds for only his brother. No groceries. Last night we came home and she asked us to go to the store for soda and waters, and she asked MY BOYFRIEND if he had money for them. Maybe I should mention, he already pays, our rent, her rent, groceries, her phone bill, in top of our bills. Another issue with the groceries is that she makes the same thing over and over knowing the 17 year old won't eat any of it, and then expects my SO to go get pizza or mcchickens for him, because she used all the money for things he won't eat. Mind you, and I love this kid, he is not a small guy, and his meal from McDonald's is around $20. Wondering what happens when we have no money? This grown woman sat there and made comments to my SO along the lines of "I guess...isn't going to eat." *Sighhh* "No food for..." Until my SO was so tired of it he went to donate plasma to get fast food for him. I'm not one to lay around all day, so I am normally moving around the house doing something at all times, but eventually I had to stop and just stay in bed, because if I made noise while she was sleeping, she would get mad and either sigh loud as possible or get up and start making it obvious I had disturbed her. When I'm sleeping she will flip the lights all on, shut the door hard as possible, start talking loud as hell, ect. And the one that makes me the most mad? She talks about me and my SO to her friend, and the conversations are always the same when they talk about him or I. Money. Money this. Money that. It's almost always one of the first things she says to him when he comes home as well. It's like him paying for ALL of her shit is not enough and like she needs more. I never ask my SO for anything, if I do it's something like dog food or kitten formula or money to go do our laundry, and yet when the money runs out for the week it's somehow crafted to be my fault we have no money. I know this post is a mess, but I am getting extremely frustrated with it all, and I can't get the thought of his family member telling me that his mother and her family dont care about my SO being well off, just if he is giving them money. Basically that she uses my SO for money. I believe what I witnessed when he had none to give was very manipulative, and I'm most afraid that my SO is going to continue to only worry about his mother, that we will never move up from this shitty place in life because she will never be able to support herself.. At the same time I feel so selfish thinking that way, but I don't see her ever being able to support herlf enough for us to be able to move forward. Have our own place, privacy, money.. What do I do? Am I the asshole in the situation ?