1. Law states that women are innocent and men does such adulterous acts. However, your husband also knew that he is married and he is the main culprit here and the law will not spare him,
2. Yes, for this act of your husband he only is primarily responsible. It will not be prudent on your part to blame the lady sparing your husband legally,
3. You will not be able to prove that your husband is innocent. It will be difficult for you to prove that your husband did not know it,
4. How can she demand money from your Husband unless he is seriously involved with her? You do not what evidence she has against your husbands's illegal relationship with her,
5. If that is the case your Husband should lodge a police complaint against her foe her claiming that your Husband is the father of her child. If DNA test proves it, then your Husband shall have to treat the child as his child,
6. Why has your Husband given money to her unless he is involved? Ask him to lodge police complaint against her such blackmail,
7. You settle the matter/dispute with your Husband first as he is the person who can solve the problem.