ANSWER:

Do not pay any attention to their comments and do not engage in any argument or dialogue with them!  If they accuse you with something, give them a big smile and do not defend yourself. This will kill them softly for failing to provoke you to respond in a negative way! After a while, they will stop such behaviors as they would sound like a dog barking without anyone paying any attention to it.

I would like to know if I am wrong or not. Being a daughter in law, my mother in law allows herself to move freely in my house( note that I live upstairs) or comment negatively on my way of cooking and my way of cleaning my house (note that i am a working mother). My sister in law also do tell me things like my husband is depressive since he got married.. how do I respond to that