Regarding my mothers sister , cousins marriage - serious advice needed

Hi IL,

A brief background about my mother and her sister. From my child hood I have seen that my mothers sister keeps badmouthing, lying and demanding about everything. I have seen my mom sacrificing everything for her little sister. She is well off when compared to my parents and always gets jealous about me and my mother. My aunts daughter always lies about me to all the cousins and i am left out from them. We are cousins of 7 and my cousin tells lies about me to all other cousins and tells them that I have told bad against them. Years passed and my mother was silent all the time and being young I could not stand up for myself in front of others.
Years passed - She , with her daughter continued the same habbit. I reached marriageable age and my father started searching alliance for me. It has become difficult task for my dad- my dad has gotten calls from couple of distant relatives warning my dad that i need to keep my mouth under control as i am stubborn , reckless etc. My dad was quite frightened about all this.
My aunts daughter marriage was fixed and she came to our house to do some course. Though we are not interested in keeping her at home we had to. One day my cousin went out with future inlaws and did not inform us nor picked up our call. Her inlaws hwever dropped her at our house at 12 PM night. They started argumenting that they would be repeating the same and it is their wish as she is their daughter inlaw. My mother was concerned about her safety and disagreed. This created small fight between both. My aunt again spread news that my mother tried to spoil her marital life etc to every one and cousin stopped talking to my mom and me. Later she is married and settled with this same family. She is 2 yrs elder to me.

After all this ****, to my bad luck i was standing in bus stop and they found me talking to a guy in bus stop at night 8:30 itseems. They spread rumours saying that I had relation ships etc to the entire relatives. Not only this my cousin has told about this to other distant cousins as well. They started belieing her sugar coated words. With great difficulty I got married to my ex. My dad out of all this ill effects felt getting me married to some guy is most important as he scared that I might be single due to bad background . My cousin had relation ship with 4-5 guys I know and had even photo graphs with one guy. Some one has sent those photographs to my dad and told him that the guy was totally lost because of my cousin. With spur of anger and way with with my aunt has created tensions in my personal life, I seriously got angry and messaged (on yahoo) my cousins husband that I would be giving complete details about her and stuff. Later , I felt why should I spoil others family and kept quite. I did not share any photographs or disclose any personal details to him . Probably this is one mistake done by me out of frustration that boiled up for the entire life. All this happened some 6 years back.

Now my cousins brother's marriage is fixed and would be conducted next month.
My aunt still continued back biting about me and my parents to every one.
My aunt has lakshs of property and keeps taking thousands from my grandpa. If my grandpa gives 1000 rs to us she takes 10000rs. She has taking lot of gold like heavy chains from my grand mother and my grand ma gave small earnings .
Out of jealousy that my grandma gave me , my aunt spilled the beans that I have spoiled her daughters life and I have message her son in law. It is been 6 years that they are happily married with a kin settled in US. I do not understand what she wants out of all this. My grand ma has come and told this to my mother that I spoiled her daughters life for which my mom did not believe. My grandma is still with us. I am quite worried about all this.
I however decided not to go to their sons marriage. Now my parents started searching matches for me again and she is bitching even more. Please advice on ow to tackle this bitchy aunt.