What to do if i m facing problems with my marriage

I am married since 12 yrs, now I am in situation that I love one lady, who is married. she is not happy with her husband, same happen in my case, so, after few month, we feel that we are in love, she run way from home 2 times for me. her family dont know about this for 1st time when she run, But when she run for 2nd time, every one knows this, her family member put her in confinement. also threaten me too by phone call. What are the proof consider for adultery? what could I do, and how we can move forward? As I know she can run for me 3rd time also. But It will not work, I know. Her Parents is also supporting her Husband, But she dont want to stay with him, She is dependent, Even if she file a divorce , Her parents will put her in pressure to take back divorce file. We dont have find the way to run away. What if she run again, and files for divorce by her side, meanwhile I just support only in financial term, In that case what are the problem, that we both face in legal term?