Asked to seduce a married man?

An old friend of mine thought is was her husbands mistress because i went on a date with him and it was nice but i didnt know that he was married let alone to a old childhood friend of mine, so she found my address in his blackberry and she came to my door all angry and yelling and well i opened and she cried and i apologize and told her i hadn't done anything with him and i never would am sorry and all, he doesn't know i know his wife. she talked to me about her husband cheating and how it is hurting there daughter and causing their son to be extremely depressed and violent, her and that they have a prenuptial and if she asks for a divorce she will lose some money and the house but it also says that if he is cheating she will get a certain amount of money and wont need to lose the house.

She asked me to continue seeing him so she can hire a private investigator and that she can build a case against him.I have never cheated in my life nor have a i ever been involved with married man, I feel bad for her and feel worse for even having a date with her man but should i do this as i do owe her and i do want him to be punished for causing such hurt to his family.

I know that if she cant prove he is cheating and she files for a divorce she will have almost nothing and will leave the house with nothing sins he is seen as such a fine sophisticated business man and she is a poor old simple minded fragile women.
This marriage is killing her.

I love her to be happy and have respect and love in her life and at the moment am kind of the only one that can help her have hard proof of evidence of his cheating since he is real careful and know that his money is at stake. oh by the way she has hired a private investigator before and was a waste of money since he is real clever.