Mental harassment

I am a hindi speaking muslim women married to a bengali muslim guy.It was an arrange marriage.I have a one year old son.This December 2016 I will be completing two years of my marriage.I stay in a joint family.My husband has two brothers and three sisters.My husband's elder sister is a divorce and stays with us.My husband's elder brother's wife and his elder sister has made my life a living hell.They lie against me.They plot so much against me that even my husband dont trust my words.They abuse me, raise finger against my character, when I try to discuss with my husband.He simply leaves the room or keep quiet but never utters a single word against them.My sister in laws dont let me finish my household work on time.They keep ordering, they keep me occupied so that I cant take rest or look after my one year old son.On top of that my husband's niece joins my sister in laws and abuse me unnecessarily. When I complain my husband about all this, he replies that these things happen in joint family, you should learn to compromise. One major problem is my mother tongue.He dislikes hindi speaking of mine.I dont know why he married me? In the month of May 2016 I came to know that my husband has an extra marital affair with a hindu bengali women.As they share the same mother tongue so my husband told me that he loves her and enjoy her company. When I confronted my husband about his affair.He denied initially but later told me that he has ended his affair.I am extremely confussed and helpless.I tried to commit suicide also.Dont know what to do? I beg, please advice.