I am ashamed to say that, to a certain extent, I did the same thing that your husband is doing. I concocted a romanticized, inaccurate memory of a past relationship instead of addressing the real problems in my marriage. Had I been confronted by my wife with her knowledge of what I was doing, I might have been more committed to working on those problems. Having some experience with your situation, my two pieces of advice are: 1)Do not give in to any urge to drink that you may be feeling. It will make things so much worse. 2) Confront your husband with your Facebook discovery. Not angrily. But tell him how hurt you are. And how you are willing to work with him to make things in the marriage better. Then, insist that you stand over his shoulder as he writes the farewell message to his ex, informing her that he has made a terrible mistake in corresponding with her, that he wants to make his marriage work, that he will be unfriending her, etc. You are absolutely entitled to that. And you are entitled to all his email passwords, and entitled to access anything he is doing online, any time you choose to check. His breach of trust cannot be overlooked and he deserves to be monitored - closely - until that trust is repaired. Good luck.