She cheated me for 2 years till I found out but is very sorry now,yet I can't forget her betrayal.What to do?

But for kids,I would not have remained with her but I don't know how long can I bear this pain.I can neither be in nor out of this meaningless relation with her.She is remorseful but where has all this guilt gone when she relentlessly pursued a happily married guy for 2 long years though he was not fully interested?I am afraid of the consequences of divorce as I had been through lot of trash in my recent past.My self-respect is still on the floor after having received the knock out punch in the form of her pionate love letter in which she was ready to be somebody's mistress(keep) than be my wife.I know she truly loved him but how can I help her in this regard after 14 years of marriage and two wonderful kids.She stopped only because the other guy cut off all contact with her.I only expected her to show me the way out or even ask me to leave her and our kids alone before her betrayal.I am thoroughly miserable and my kids are getting tired of seeing my sad face everyday.Please suggest