Yup, I am thinking he needs to hear it from an objective third party... interlopers in marriages are lethal... you learned that the hard way...

He's not going to hear it from you.. He's still blaming you for hurting him... he needs to realize you were vulnerable and OM took advantage of you... but he is too hurt to assign blame fairly here...

He needs an objective third party, he wont' accept education from you no matter how good a quality it is...