What do I need to save my marriage?

It is very confused for me. Last March she went with her first cousin Helen to the event for weekend. She came back home and act weird then asked me to leave, separate. She said she don’t miss me and don’t in love with me. I left and in about less than 2 weeks separate and she want me back home with her she said she miss me and very sorry about what happened and hurt my feel. We went to marriage counseling 2 times and we are doing fine and go church together every Sunday ever since. On Christmas day we had good time and then Monday December 26th she had to go SC drop son off to son’s father…Helen was with Denise. After drop Noah off they stayed in SC few days and came home December 29th she act weird, and told me she want go with friends for college bowl game. She act weird, then she don’t come home and told me she was so sorry she drunk and stay at Helen house. She came home and still act so weird. I haven’t figured out. And finally she ask me for divorce and I beg her not to divorce and ask to try separate little longer and she said I think I made my mind up already and it is over. And she said ok I will do this for you only for separate. So I pack my clothes and left to stay at my dad house.
I came back other day to get dogs, I realize it she took pictures down a pictures of us in bedroom and living room. It is much worse than last March. My sister in law said she think first cousin Helen had alot to do with it cause my marriage messy.

I’m so heart broken, and I need your help what I can do to help my wife and save my marriage. I forgive her but she has to stop doing that with Helen like party and getting drunk. This is second time in march and last week. We had been doing fine for 8 months after separate last march.

But she said she think she already made up her mind and will not change it that what she told me last Friday night. I do not understand why she ok with when I beg her not to divorce but to try separate little longer but she only said I’m doing this for you only.

Is there anything I can do better job on my marriage and what do I need to do during separate? She is 40 years old hearing and and I’m 31 years old deaf. Noah is my step-son and we have granddaughter from my step-daughter. I was there when granddaughter born last year she called me papa all time. I’m so confused why would this cause happen my marriage.

I thank you for read my letter.