My husband is my “slave”????

So my SIL who has never been married has now insisted that I treat my hubby (her eldest brother) like a slave because he does the dishes and takes out the trash for me. He also helps with other chores around the house. She thinks I boss him around and he does all the work while I sit back. My hubby and I have agreed that the work in the house is split. He knows I hate doing the dishes and he has always taken the trash out. She doesn’t think that’s how my marriage should go and now is talking crap behind my back about it to her sisters and they are all stand offish around me. I thought we had a relationship, and a good one at that. But I guess I’m wrong.