I actually believe in ironing out creases, not throwing away the garment or destroying it.
Where I am standing I feel all three of you involved in this awful mess are victims. Yes there have been haram acts committed but I do not like to judge since I am not GOD.
What is the best thing to do given the situation?
Lady A is obviously forced into taking a decision under pressure from her family through their evil caste crusade. Love is not something one can put out, just because she forcibly married someone else does not mean she is over you or should be expected to she is a human being. It looks as though she does love you, is stressed from the guilt she is going through. Her husband, is he really her husband when she has not accepted him from her heart? (this is what it looks like). Whether you and her get together or not she needs to leave her Husband who is in a sham marriage, he deserves a chance to be happy in life and deserves honesty. With you, you need to ask yourself a serious question. Are you willing to marry her if she divorces her husband? (considering it may not be her fault that she has been emotionally blackmailed by her ruthless Parents). If it a yes then atleast two people can live together happily out of three unhappy people, she must therefore divorce her husband asap and marry you regardless of her parents pressure. If the answer is no, then confront her and tell her your decision. Infact start looking for a partner if you want to move on from this. Don't involve the Police just tell her and she will surely move on when she knows you are with someone else; she still thinks she has a chance with you.
Adopt forgiveness and learn to forgive people, holding grudges is bad for your Nafs. If you can forgive her then do but do NOT ever bring up her past and if you are uncertain you can do this then move on-in either case forgive her and tell her that.
I can no more understand the totality of God than the pancake I made for breakfast understands the complexity of me