Advice please 😞

So my mother-in-law was suppose to move in for a few months so her boyfriend could get in his feet and get an apartment for them. I agreed and said it was fine. Next thing I know she moves in and is talking about when we buy a new house my husband said she can live in our basement. When I asked him about it he said he didn't say that. But whenever I try to talk to him about how long she's going to stay he starts a fight and says he can't believe that I'm questioning helping his mother. I don't mind helping her but she babysits all the grandchildren, and now his sisters are always at my house eating my food and they are so loud. I can't enjoy my days off. I can't have alone time with my husband. We haven't even been married for 6 months. I'm not ready for something like this. Am I wrong? Is he wrong? I don't know what to do its so annoying. This isn't something we agreed on