Of course you feel low. Instead of feeling loved and appreciated, you feel like a servant in your own house. Your mother-in-law (MIL) has lived with you for 5 out of 8 years of your marriage, and yet she mistreats you and tells her son his marriage to you was a mistake. Worst of all, your husband hasn’t found a way to make it clear that his choice is a choice of love, not an insult to his mother.
It may be that the root of the problems is a difference in expectations and assumptions about family life and loyalties. You are an educated woman who probably has expectations for a partnership with your husband that takes priority over his relationship with his mother. MIL may have the expectation that her son will continue to put her first and that the role of a daughter-in-law is to satisfy her every demand. I am very concerned that your husband was about to hit you when you were upset with his mother. That tells you that either he agrees with his mother or he is a man who doesn’t know how to deal with conflict in a constructive way so he resorts to a threat of violence to just make it stop.
You didn’t mention how the decision was made that you and your husband would share your home with your MIL. Did you and your husband talk about exactly how long she would be with you and what you could expect of her as a member of your household? Or did your husband and his mother assume that a three generation household is the norm where your job is to take care of all household tasks and that you would be in agreement? IIf that was their expectation, it is likely that both your husband and MIL are surprised and disappointed that you have a different point of view.
Ideally, this would have been talked about well before you married. That doesn’t mean that you can’t review those decisions now. Unless and until the three of you, (you and your husband and his mother) can come to an agreement about the roles of the adults in the family that satisfies all of you, this discord will continue and you will be more and more unhappy in this marriage.
For now, I strongly urge you to find a way to ask your MIL the same questions about what she expects without showing your anger. Ask her how her mother-in-law treated her. That may give you some insight into her behavior. It might be helpful to point out that what you have in common is love for your husband. Since doing everything for everybody is wearing you out, it might be helpful to tell her that and see if there are some tasks that she might be willing to do. Express appreciation for any efforts on her part. It will be hard for her to change.
I don’t know what services are available in Malaysia. In America, I would urge you to see a family counselor to help you all figure this out. I hope there is a neutral third party who has such skills in your country. You could all use that support. If your husband and MIL refuse to work with you on this, you are left with only two choices: Either you will have to separate or you will have to find out a way to manage the current situation. Either way, MIL is your son’s grandmother so it is best if you can find a way to be civil with her, even if you feel she doesn’t deserve the courtesy.
I wish you well.