Matrimonial

Dear Sirs This is question from my friend this is between A- husband B-Wife C-husband D- wife. Now the brief; A&B are facing divorce case in court.filed by wife who is residing somewhere else since back 4yrs saperate same C&D are also under divorce case, C is also facing Case of adultery filed by his wife D.both living separately. The situation is, the husband A is in affair with wife D and want to marry or want to be in Live in relation. this matter exposed and wife B came to know about the love affair of A&D & started demanding high price can say extorting for settlement in divorce case which A is unable to pay as alimony. My query: Can A&D marry or stay in live in relation because Div case will run endless time. May pls resolve as A&D wants to marry or want to start live in relationship. pls advice the legal consequences which will arise either in case they marry or they start living in relationship.