What would you do?????.....

Saw something interesting and wanted to know ppl's opinions.......
What would you do if you met someone and became best friends with them...you find out they're married . And they confide in you about their life and marriage....how the wife treats him like crap, physically, and emotionally abuses him, and you fall in love with him and he falls in love with you.....you've basically been emotionally attached to each other for 4 years..... Would you up and forget about him or stick around with no guarantee he'll ever leave the wife, bc they usually never do....?