Why after [3, 5, 12, 25] years does he still spew hateful venom at me. He's the one who cheated, he chose to leave and now he's living with the alienator.
Because he has a loud guilt screaming in his ear and he's needs to make you the bad guy to keep up his hatred. He has to convince himself that you are bad, worthless, useless and that you got what you deserve. If he's mean, you might even help convince him by reacting back to him. Venom spew is a negative affirmation; if he repeats the negativity enough he will believe it. Please understand this, he won't merely believe his lies but he will genuinely remember his rewritten version of history as real. Your MLCer and the alienator may both have been married and in MLC and both bear the responsibility for destroying the lives of not one but two families. Justifying the behaviors does not remove the guilt, but it alleviates it as your MLCer feels entitled to attack you because everything is your fault; you made him miserable.
Not all MLCers will spew Monster venom and not all who do will continue for years. But sadly some do and some will come through their crisis but will maintain a space of internal denial where you remain the enemy. They may live full and beautiful lives accept when they think of their wicked ex-spouse. Developing a relationship through the years may prevent or disintegrate this hatred as they can face reality through your actions, detachment or genuine kindness.
A spouse is the closest confidant we have--ideally. You know your MLCer better than anyone--possibly better than he knows himself. He knows this. If he thinks about you as you truly are he will look into your eyes of pain and see his reflection. He cannot bear that burden of responsibility. He will look in your eyes and see the truth and reality of who he is becoming and the pity you feel because you see into the core which he keeps hidden from everyone else--including himself. Venom spew distorts the mirror he sees in your eyes.
He got the life he wanted, so why is he still angry at me?
Do you really believe that he got the life he wanted? He didn't. In his fantasy you didn't care about his affair and might have even become friends with the alienator or you dropped off the face of the Earth. Your children adore her and she became like a mother and her children adore him like a father. But in reality his children hate him for what he's done to you and them and her children are even worse toward him, so much so that he's come close to physically hurting them. He cannot discipline her children because she yells at him and they pull out the your not my father card. They argue over the kids, bills and about their arguing; he drinks and she nags.
I want to believe all of that, but it seems pointless. Is he going to hate me forever? Is there a way to change it?
Yes and no. You are right, though the psychobabble may be informative, what do you do with it and how do you build trust when you’re the enemy in his crosshairs? If you want someone else to change, start with yourself and they might choose to react and respond differently, but it is their choice. You will have more direct options for interaction if your MLCer is in communication with you. For those whose MLCers have disappeared completely, you may need to be patient for an opportunity; if you know how to reach them you have options.
Refrain from defending yourself and directly stating that he is lying or that he is wrong. This will only incite the Monster and cause an escalation. Of course be cordial and kind, but there are times when it is appropriate to comment. Practice and prepare what you are going to say--write and revise. There is nothing wrong with talking on the phone with a script, but practice so that it sounds natural. There are three main components; the sub-steps are merely examples and may vary with each situation.
Validation is a standard start to ease into the facts and soften his reaction--though most MLCers will still react with anger, defense and accusations. They may privately acknowledge the accuracy of your words but show defensiveness and anger to save face, or they may deny your words and only acknowledge them later while processing. Next by pointing out things that he might defend (justifying adultery) or counter you can override his defense before he gives it. Then follow by connecting those facts with a since or because. By establishing the facts that are public and obvious you can make a smooth transition to pointing out how others have understood them which then leads to his knowledge of the facts. This isn't psychology; it is showing the evidence to build your case. Since other people understand the facts and since he is a (supposedly) rational, sane and intelligent individual it follows that he can see events from their perspective. This may not be true at this point; you are planting seeds. I did the same thing with you a few paragraphs ago when I challenged the statement about believing that your MLCer got the life he wanted. I didn't follow all of the steps; you're not in MLC. But I showed you the other side.
I’m sorry you feel that everything is my fault and I made you miserable. But everyone knows that you cheated and left me and the kids. Misery is not a justification for infidelity; there is no justification for infidelity. Everyone knows what you did and since there is no justification, they know I am not the enemy and they disapprove of your actions. You know perfectly well that you I am not the enemy, I did not make you miserable and your sorry life is not my fault. Go ahead and continue to run from it, it won't change reality.
Not everyone disapproves. Your MLCer may have painted horns on you so convincingly or with such affirmative repetition that those who knew both of you may believe him, or doubt what they know about you--this is especially true with your in-laws. But someone disapproves; even if it is only you. Connect the dots to show why. Then let it go. You spoke, now let your MLCer interpret and process on his own.