He is oblivious to my anger about the alienator; like it's no big deal.
This may change if you start speaking with more authority and continue to remind him of his immoral behavior--use immorality words like cheating, adultery, affair, infidelity, whore. He can act like and even believe it's no big deal if it seems to him you are acting as though it is not a big deal. He may or may not reveal a change to you and may instead maintain the act. Though many are not able to maintain an act in the face of direct opposition and accusations from their spouses. He may try to become defensive:
That last one may be used by a man who is not trying to leave his marriage, but may also be used in exasperation to show that sex isn't a big deal or meaningful--even if he wants to commit to the alienator, or he is trying to get a reaction from you.
Standing involves consistently throwing his actions back in his face as he tries to deny, dismiss and diminish them. I'm not talking about lying about them, but that he tries to make them unimportant. The challenge is that you need to balance your firmness with softness. Too much authority and you are intimidating or an Angry Bitch; too soft and you are a doormat.
I've read that we should be cordial to the alienator and not to bad mouth her. It sounds like you are recommending that we put judgment on her and our MLCer for the infidelity and lying. Doesn't this go against validation affirming and lifting him up?
You are allowed to hold a mirror up for your MLCer to see his reflection. I don't recommend bad mouthing anyone--bad mouthing is empty insults. The truth is not meant as an insult; it's the truth. There is a time in the crisis--usually early--when many MLCers do not consider their affair adultery. They feel that your marriage is over, that they no longer are in-love with you and that this justifies starting a new relationship. Deep down they may know their behavior constitutes adultery, but in order to continue the affair, they have buried that notion. Let them know that their behavior is not acceptable. They will become angry, but it is also information they can consider and process--they may not have thought if it that way before.
But before you hold up the mirror, stop and consider your individual situation. Is this early MLC? If early, your MLCer is likely under the influence of in-fatuation--his relationship with the alienator has not progressed to the destruction of the fantasy. When in-fatuation is high, the alienator is the perfect blend of feminine beauty, innocence, sexuality and purity. If the relationship is at this stage, he will defend her at all cost and demonize you with increasing ferocity if he feels you are speaking badly about his perfect woman.
It is important to speak in generalities rather than specifics. Instead of insulting the alienator personally, state truths (as you see them) about all people who engage in relationships with someone who is married to someone else. If your accusations are empty, it enables your MLCer to dismiss them and defend the rightly alienator. Recognize your bias. Your MLCer's alienator is not some alienator referenced in a book; she is a real person having a sexual relationship with your spouse and intent on destroying your marriage. It's personal, isn't it? Neutralize her. At what point does your bias consume all facets of the person? Good people make bad choices and mistakes. The alienator may be a loving and talented kindergarten teacher, a singer in the church choir, and a homeless shelter volunteer. Or maybe not, but then she has different good attributes.
The irony is that actions take time for processing by the MLCer and often you will think you were right in your predictions because their initial actions match them. Just remember, MLC takes Time.
Have you have been trying to predict your MLCer's responses and using your predictions as excuses for why certain actions will not work and thus why you shouldn't try them? Are you tired of picking egg shells out of your feet, placating him with yes dears, and calm down honey's, and apologies? If you are allowing your fear to consume you and enable placating behavior, you have likely landed on the doormat.
Going from the doormat to Bitch-Mode is different than falling off the tightrope from a place of strength to Bitch-Mode. Those who are strong may have the ability to lean into Bitch-Mode without falling. The doormat pretends all is well, there is no alienator or go ahead be with the alienator too, life is good, the marriage or separation is perfect. It is not merely a state of powerlessness where one allows one's Self to be walked upon; it is also often a state of denial --deliberate or false. But MLCers are lost. They may misunderstand such behavior. When doormats become Bitches they are out of control--many doormats regularly cycle to an uncontrolled Bitch-Mode. But coming from a place of strength, the controlled Bitch is not negative.