FAMILY IN LAW, BAD OR GOOD?

I've married to my husband for almost 8 years and have three kids( 2 boys and 1 girl) but i still can't suit myself to my family in law because of their behaviour.
They likes to compare my children to theirs and they always said that mine is the worst.. it's really hurt to hear them saying nasty thing to my children yet i can't do anything because of my hubby.
They even dare to beat my children right to my face.......Sometimes i feel like i want to burst out everything to them.. I really want to tell them that they're not perfect either and their children is not perfect either. Why should i respect them since they never respect.
Maybe my 2nd and 3rd kids won't understand anything yet, but my eldest son did understand what they said to them.. there was once he ask me " mummy, why mak su and mak ngah always call me weird? am i really weird?" My heart wrecked but all can i answer is they are just joking, don't mind them.......
Other people may not agree with me but to me family in law never bring good in my life. They only bring heart-brek and sadness in my life.