Torn About Leaving House

[Portent]

When my wife and I were dating she told me she was bipolar. When the devaluation phase came I thought it was the BP. When she dropped the bomb on me that she couldn't keep pretending anymroe, didn't love me anymore, was having an affair and wanted a divorce we made an agreement that I would stay in the house until out son was at least 3.

2 months later and realizing that she is a pwBPD and now BP I'm torn. Our relationship is poison. My birthday was yesterday. She first tried to ruin my birthday by changing her scheduled business trip so she would not be there. She dropped that bomb on me days before. I told her 'I knew you would do this. I've been preparing to have a fun party without you. You cant hurt me anymore.' She later asked to take me out to dinner on the 3rd as a birthday gift. Then she changed that to I'll cook you a dinner. Ultimately she threw a plate of food on the table and told me to eat and shut up. I had hoped to have an adult conversation with her about anything but our relationship. She told me that she didn't want to talk because my passive aggressiveness just starts fights. I've got to say I was ready for anything. I was ready for her to kick me out of the house. I was ready for her to fake an assault and call the cops. I was not ready for the callous way she treated me. Its the most I've been hurt since that day she told me our marriage was over.

I know that for me I need to go. But for my kids, and yes I consider my step kids my kids. She may have given me love, or at least I thought it was love, those two gave my previously shallow day to day life meaning.She is in therapy primarily to be a better parent. I'm worried about our stepson. My presence at the lest tempers her verbal abuse. Especially since she knows that I want to see improvement with how she treats him if she expects me to not fight her on custody with our own.

Then of course I love my time with those kids. If I move out I wont hardly see them anymore. And they know that I'm supposed to stay another year. If I leave now they will be devastated.

And then of course there is my son. I dont want him going between houses yet. My parents were divorced by the time I was 2. I had wanted to save our marriage for him. I'm the only one who gives him real love. My wife is incapable of it. If a day has been bad she totally shuts off from him and  is a zombie. I dont want him dealing with that half the time.

So here is the question, should I stay or should I go? I know the damage its is doing to me. I'm her trigger and she wants to vent. With the mask she has to wear at her job and with her new BF who is a shallow replacement for me, all of my faults none of my redeeming qualities, she has to release her negative energy and I'm the target. But if I'm not there my stepson and eventually our son will be the target. At least I can rationalize it. At lest I can take it. I'm even getting far better at verbal judo, it helps having studied judo since I was 11, and I can diffuse the situation more easily.

If I do stay what should I do to limit the conflict. I'm trying to keep it as transactional as possible but she looks for fights. I mean honestly picking a fight over me picking fights. That is way messed up even for her.