Do I act as miserable as I feel or do I act like I am fine? When he calls should pretend I am fine or even happy? But will doing that eliminate his guilt? If I act depressed--which is real--will he stop calling or coming around?
Your MLCer will be as confused by your behavior as you are by his. Crying, depression and begging and pleading are expected and normal. An MLCer who is an Ego-Deflater may be surprised when you react this way because he did not believe your love was genuine. If you behave out of the norm, such an MLCer will believe that this validates his belief that you did not really love him and that you are happier without him, whereas victim behavior will disgust an Ego-Inflater who did not doubt your love and who considers such behavior a sign of weakness.
What this does is bring up a new question. Should you show your true feelings which are presently of a victim with an MLCer who doubted your love and feign happiness with an MLCer who did not doubt your love? Before answering, consider the circumstances of each behavior with each type of MLCer.
Victim with Ego-Deflater
A Deflater is already prone to seeing himself as a victim. Are two victims better than one? This MLCer manifests his feelings of unworth openly. He wants and needs reassurance of your love, but consider whether mirroring his victim behavior is an affective method. A victim wants someone else to solve his problems; your MLCer is not presently capable of solving your problems but may feel responsible for them anyway, this will only increase his guilt and feelings of worthlessness. Ego-deflation is a mask for anger; a Deflater fears his anger and thus suppresses it. If you take the victim role too far, he may explode into what will seem his opposite--in midlife crisis, he may be doing that already.
Victim with Ego-Inflater
Signs of weakness disgust this MLCer, but at the same time your reaction validates his feelings of superiority. He must be pretty awesome if you want him so badly. He must be a great guy since two (or more) women are fighting over him. He will continue his affair and may taunt you with his infidelity because it maintains the high-level of drama that is his narcissistic supply.
Pretend happiness with Ego-Deflater
This answers his fears; you never loved him, otherwise you would be sad and crying. While he wonders this, there is another nagging question or curiosity in the background of his mind; he may be aware of it early or it may surface as he progresses through the MLC tunnel. What is she doing that I'm not; how is she so happy? What is her secret? I want some if that. Joy is infectious and attractive. Initially he may react with greater depression when he believes your joy--or well acted false joy--means you do not and never loved him. Misery may love company, but it thrives nowhere. Two depressed victims in a relationship are co-dependent on and thus stuck in their shared misery.
Pretend happiness with Ego-Inflater
He cycles between relief that you are not standing in his way to attempts to incite you to argue since you are not providing him with narcissistic supply. He will accuse you of being in denial and of faking your mood. Since you may be faking, he is trying to shoot down your attempt so he can feel superior and strong. He will taunt and tease, charm and argue, trying any number of tactics to break your facade.
Love your MLCer from your strength rather than within your weakness. Do this by becoming strong and choosing joy. Since this is a process, you will experience periods of melancholy, you will feel anger, depression and fear. I've reviewed a few circumstances but provided you with no answers. What does that mean? It means crumple up the above circumstances and throw them away. How should you act? Well, I'd rather you be than act, but making believe can manifest reality: fake it 'til you make it. I recommend that not because of what your MLCer will think or do, but because it is beneficial to you, the benefits to your Stand are byproducts, but if it were something that were beneficial to Standing and detrimental to you personally I would not recommend it--and in actuality if something is detrimental to you it is also detrimental to Standing. Notice that the phrase is not fake it forever; the word until places a limit on how long you are to pretend. You are faking joy as practice for being joyful.
You are not going to stop his crisis. How you act now will not stop the crisis, erase his infidelity and bring him home where you will pick up where he left you off. It's not a train station; it's a train wreck and you both have to repair your Selves before you can repair your relationship--since your individual Selves are the foundation for your relationship. But you are presently worried about his present reactions. Regardless he will react and his crisis will get worse before it gets better. Being a victim is not beneficial to you; it weakens rather than strengthens and is thus not Paving the Way home.
Pretending that you are happy is not about being perpetually perky--get those pom-poms out of his face! It involves being real and part of that is practicing being joyful so that it becomes real. It also involves being sad and being angry. It is okay to confirm to your MLCer that you wish this were not happening, that you miss him and that the circumstances sadden you. But let him know only in an informational manner rather than through showing those things with emotional energy that is or risks becoming uncontrolled. Let him know that regardless of the circumstances you are choosing to find and create joy in your life.