How do I walk out of this abusive marriage?

Photo; Courtesy

I have been married for nine years and have been blessed with a son. However, my husband has never gone to my parents and only visits home when there is a function. Since I am jobless, he has always taken advantage, often beating and insulting me at will. For two years, I have been in a relationship with another man who wants to marry me as a second wife. He has made arrangements to meet my family and pay dowry and he even has identified a house he wants to buy for me. He really loves me and he is the one I want to be with as my life has been hell. He has accepted my son and I think he is serious about marrying me. My parents don’t have a problem and have accepted to meet him. Please advise me on what to do...{Waceke}