What can I do to make my mom allow me to live my own life?

I'm an only child and my life has been miserable. I am thankful for my mom. She do a lot of things that other moms won't do. Here is my problem, my mom want me to be up under her all the time. Its like if she doesn't have my whole attention she gets jealous and she become verbally abusive to me. She always acted this way when my cousin comes around. We are the same age and of course we have a lot in common. I have kids, they have right to be around their grandmother but, sometimes I wish I didn't have kids and I would have moved so far away from my mom. Maybe out of the country. I'm also getting married soon and I know my mom is going to make me choose her or my future husband. What can I do to make her cut the cord and allow me to live my own life or what I need to do to get away from her and her childish behavior. I'm tired of having to walk on eggshells around my mom.