Love/Pain

My husband and I have been together for 8 an a half years. We have a 2 year old.  We've been married for 1 year.  He had an Affair in Sept. and had serious feelings for the "mistress".  The "mistress" also had feeling for him.  My husband lied to both of us not once but twice.  The first time he lied, is when I caught him on myspace talkin another girl the "mistress" well I got in contact with her and now we are friends and I care alot about her.  We all talked and they (my husband and the "Mistress") both agreed they were just friends even though they had feelings for each other.  Lie number 2! Today I find out that the "mistress" has very stong feelings for him and that he was telling her he wanted to be with her.  All while he's telling me he wants to be with me.  He also has strong feelings for her too.  I told him serval times we cant be together becuase I cant trust him.  So now we are getting a divorce and we are seperating in 6 months.  I can not describe the pain or the hurt in my heart. I loved him so much, but now were are finally done.  I have cried all I can cry and now I just want the best for our son.