My sister in-law maltreats and disrespects me. How do I stop this?

Please hide my identity, I am in my mid twenties and I have been married for only a year. My husband treats me well and I am really lucky to have him as my husband because he is so nice, easygoing, hardworking, young and caring. The major problem we have is that he doesn’t have money. He is struggling to make ends meet and so many times, we do not have enough money to even put food on our table. He is very hardworking which makes me love and appreciate him the most. He tries out a lot of things, he sees clothes, sometimes he works as a driver for one of our neighbors who runs a pure water company. I am working hard too to contribute my own but it has honestly not been very easy for me and my husband. Things are very difficult right now that survival is even challenging. 

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Because I try to help my husband, I started a small business. I started cooking rice and soup to sell. I usually get up very early around 5am to start cooking and because my husband is usually tired from work, he rarely helps me so I have to cook the food all by myself. When I started, I started on a small scale so I used a small warmer. I had to put the food in. However, after the first week of my business, I realized that sales were improving so I decided to increase the quantity of food I make but my major problem was where I would put the meal. My warmer was small and couldn’t contain the quantity of food I cooked. I thought of putting the meal in two separate warmers but when I thought critically about it, I realized that I didn’t have enough space for that. 

I had to borrow her bigger warmer. She willingly agreed to give me the warmer. I have been using it for my business since and hoping to buy mine and return hers until one day when we had a fight. She cursed me mercilessly and said a lot of mean things to me. She insulted me about not having a child for her brother. She also said I borrow things a lot and asked me to return her warmer. People were watching, she insulted me in front of the neighbors just because she had more money and was doing better than my husband and I. When my husband returned, I told him about what happened, he was very angry. 

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He tried to confront her but she didn’t even listen to him. Since then she has been treating me in a very demeaning manner. We live in the same house and since my husband cannot afford to rent another house at the moment, we are stuck in this place. I have been trying my best to stay away from her and her troubles but she always finds a way to get involved in a fight with me. I hate that my marriage is going this way. I hate that I constantly have to avoid her. My marriage is not even up to two years and it is going this way already. She is not married but is making money which gives her the nerve to talk to me the way she does. What do you think I can do to stop this insult from her?