C.P.
You have gotten some fine advice, but I would like to offer a slightly different path. Before contacting an attorney, I think she should contact a counselor. I think BOTH parties need to work though the issues, and this can be facilitated by a professional. Maybe even before that, she needs to worry about how to support herself and her kids. If she is a stay at home mom, she needs to get into the job market, or train for some profession. Prepare for a nasty divorce, but expect a pleasant one. She should continue to try to be understanding and kind to the man she shared her life with and who fathered her children. If this is impossible, she at least needs to keep her anger to herself and remain cordial. No matter what mistakes he may have made, he diserves to maintain a good relationship with his children. Under no circumstances should she try to put them in the middle of the parents fight. She needs to do her best to keep her arguments with the father of her children away from the children. They deserve to be in a loving relationship with BOTH of their parents, to the extent the adult is able to do so. Finally, but as a FIRST step to resolving a relationship, I recommend "Getting the Love you want", a guide for couples, buy Harville Hendrix. (There is a companion book for singles called "Keeping the love you find".) This is an old book, but can be found used. If their relationship is not too damaged, this book can help them repair the damage. Most people enjoy the activities in the back of the book, particularly "re-romantisizing".