Is divorce the right decision?

2 weeks ago i filed for divorce from my wife Kaleigh when i woke up in the morning i was having 2nd thoughts. When she found out she start crying uncontrollably telling me how we have barely been married and how much she loves me and that a divorce would break her heart. We have been married a little over 3 months and it has been nothing short of chaotic. She is an alcoholic and she told me she doesn't have a problem. A week after the wedding she was arrested on her 2nd DUI and lost her license. I knew she was alcoholic before i married her but she swore she would go to AA after the wedding and sober up. I had never seen her breakdown and cry and changed my mind and never had the papers drawn up. I went with with her to her first AA meeting. I thought she was still going to AA when she called my at work from jail she was arrested again this time for public intoxication. She told me she had only went to the one meeting and that the people their were too judgmental. I'm pissed and sick of her bullshit i love her with all my heart but i see almost no alternative then divorce. My EX girlfriend who is the mother of my 5 year old daughter told me it was a mistake to marry her and she won't change for me. My EX and i are getting along for the first time in years and she has told me she wants to get back together and be a family. My daughter would be so excited she always wanted to be a real family and she doesn't get along with Kaleigh either. However i feel like a divorce would be quitting on her and i am not a quitter. However i feel like i have done all i can do. She opened up to about her childhood which she had been reluctant to ever discuss she told her dad used to beat her mom and her at her and her sister. He was an alcoholic and she started drinking with him so he wouldn't beat her so he could have a drinking buddy. Her parents divorced soon after.This explains why i never met her parents or her sister. She told me she would go to counseling to sort out her past. I don't know if i should believe her. what decision is the right one?