I would put my foot down and tell her to stop being selfish, there is a child to consider and you made a commitment to work through things and stay together. Whatever you do don't beg or plead with her or say you will wait while she " discovers" herself etc. If she walks then cut her loose and concentrate all your energy towards yourself and your child. If you have done nothing to provoke this then I would be taking steps to leave with your kid. Let her be the one to come home to an empty house and wonder what happened. Maybe then in a month or two of her going crazy she will come to her senses but I wouldn't count on it.