Well, I don’t agree with Nina in the way she pushed you to confess with your husband about cheating him.
I would say that she somehow “keep an eye on him” for a while. When you reveal your secret to her, she found it as a “once in a lifetime” opportunity to ruin your marriage and intervene in your relationship. She tried to manipulate you to tell him. But you didn’t have the balls to do so, she finally did that for you.
She wanted to do so badly, the feeling of destroying your relationship was so strong that she took the phone and tell him on behalf of you.
This was planned ahead. I am not saying you were right to cheat your husband. However, you could keep it yo your self and move on living with him to see if your relationship worked out or not? If not, both of you could file a divorce to live a new life and you keep your integrity.
I think during the divorce process, Nina approached your husband and act like a “saint” to help him out. She felt empathic for him and then took his heart. That why she told you “We have a spiritual connection”.
Dating your best friend’s ex is very complicated and usually, this is planned ahead, just wait until the opportunity come and then action.
The lesson I learned was a while ago: Don't meet your girlfriend’s best friend. If she hates you, you will be in trouble. If she likes you, you will be in Big trouble.
