It doesn't matter if you cross the T and dot the i or what the middle initial is... .the behaviors are clearly negative and clearly negative life *patterns.*
she finds out about his latest romance and goes thru hes email and finds emails from over the years from a bunch of ex-girlfriends.
He has triangulated you with not just his wife, but the many replacements that came before, possibly during and of course, afterwards. For some reason you know allot about these replacements which means that the boundaries concerning privacy are non-existent. That also means that your privacy is not being protected in the pattern. The knowledge of the ex-wife and ex-girlfriends you must admit, also implies they know of you.
The betrayal of his wife also cannot be overlooked or downplayed as a factor in the drama of the marriage. You and she are in the same boat as women- but she has legal ramifications- she may need to fight for control of the non existent boundaries and put them in place before she jumps overboard as the marriage ship capsizes- hence her anger is justified as she tries to steady the boat and get things on an even keel- probably very difficult for her as her husband scapegoats her to you and to others.
He said that he doesn't even know what love is and that he is incapable of loving anyone.He said that the mood swings that he goes thru are killing him and that he doesn't want to continue to hurt people anymore.He also said that he doesn't want anymore serious relationships right now,that he needs to work on himself and seek professional help
He seems to be quite up-front with you about his disturbances which gives you an "out" without blame. This is a gift he is giving you- he accepts responsibility- although it's at a victim stance. Does this make you still want to stay involved? Perhaps his Wife also wants to remain involved- that way he can remain in the marriage with the thinking that he's permanently a victim.
Did you feel like you could aid him in his quest to escape her and life a happier life? The pattern of instability in interpersonal relationships causes people to feel certain attractions- especially concerning Victims and Persecutors and fulfill childhood schema's (a hidden need- also a pattern) to step in between the two arguing parties and rescue one of them. Do you still feel this way or are you suffering guilt by letting go of the idea?