No, you cannot forget what she has done. She hurt your family and has not addressed it. That means either she feels it's no ones business or she is afraid to address it with all of you. She may also be going through something that is affecting her. Sometimes when people have unresolved issues, they push down their feelings until one day they cannot cope anymore. They make a radical change in their lives cutting off what they knew and starting over, essentially. The popular term is mid life crisis, and it is a crisis of identify and facing middle and older age. They feel their old life is not working and by changing things, they can have better control.
She may feel that addressing it would bring up too many bad feelings and she would end up a single person fighting a family. Many people would avoid such a situation. She may also feel defensive about her choice because she knows she has hurt the family.
The best option is to try and talk with her individually. Make sure you are alone. Bring up that you understand she has made a choice and that is ok. Stick to addressing your feelings. Tell her that her choice had effects and that these effects are hindering your relationship with her. Let her know you'd like to clear the air. Then see how she responds. Her response will tell you a lot about where she is at with her choice.
You also may want to suggest seeing a neutral third party to talk this out, such as a counselor or pastor. That would help each side to feel protected and would also give some guidance to the discussion. If she refuses to do this, you and your family may want to consider going yourselves. It would help you heal as a family.
Regardless of what happens, keep in mind that she made this choice because something was wrong with her feelings. There are unresolved issues for her. If she felt ok and she was healthy emotionally, she would recognize what she has done and repair the damage. As a result, this is not an easy situation for any of you.
I hope this has helped you,