Extra Matrimonial Affairs - The outsider should pay for pain caused!

I am a mother of a 5yr old girl, who has been going through hell for the past 5yrs, because of a mistress that decided to continue to see my husband in an extra matrimonial affair.

1. Why should one have to go through that?
2. Why are the outsiders given the chance to break into a marriage God has put together.
3. What has happened to our morals?
4. What example are we are setting for our children?

Following is a part of an email wrote previously by this woman to me and I will not show any names. I am just sure many people have received similar letters, and would like to help me put a stop to this.

"V has told me that he has forwarded you the divorce papers and now you refuse to sign. He says that the Divorce will still go through as he does not need your signature. I thought you were no longer in the picture. He says that he barely talks to you. As you probably know, he is always in Canada. He has said that he was trying hard to make it work and that the divorce will be final soon. He also tells my family and friends that we will be married by 2009. K you and I both know that we cannot share. We both deserve better and that is not a very sane thing to do. You are wrong as I would need for you to be out of his life before I could ever move on.... that is if I were to move on. The baby is already 3 and a half and I cannot believe this is still going on. I get the feeling that both you and V may not truly want a divorce. If that is the case, Stay together. I will leave you and your family alone. V knows the terms of the FINAL ultimatum so if he does not deliver, that is his choice and I will leave YOU and YOUR husband alone."