QT, you are doing what is right. You are trying to save your M. and that is right. Everyone asks me why I would want to stay w/ someone who has left me for another W and while I am pregnant w/ a baby who has a heart defect. I simply say that if my M ends at least I can say that I gave it my all and made myself better in the process. So don't give up until you feel that you tried your best.
