free at last

I was married to my ex husband for 17 years when last August he sent me a Dear Jane letter via e-mail telling me that he was leaving to find happiness. Suspecting that "happiness" was yet ANOTHER affair ( six that I know of), I hired a private dectective and proved myself right! He is now living with his "happiness" and her four kids,planning to get married as soon as our divorce is final. Here's the kick in the story, this woman is everything that he loathed in life and in a woman in general.  She is from the "other side of the tracks" low life, of low moral character and a basic all around sleeze bag. By all accounts, he is living in the 1980's. I know this because he documents his life on Myspace daily. He believes he is still 25 and in the Marine Corp ( his actual age is 49).My question is, is this a product of his bipolar condition? The way he is living  his life goes against everything that he believed in.Is he trying to prove something to himself or to the world?