Hi mate,
I think the fact that you are posting this and saying you are tired of living this way matters. Remorse does count, but remorse is only the starting point. The next step probably is not trying to convince your wife that the account was incomplete. The next step is showing her, over and over, that her boundary still matters even when you are angry, hurt, splitting, embarrassed or wanting to get even.
From the outside, the Instagram thing may look different to her than it does to you. You are seeing it as, “I realised I was making a mistake and stopped.” She may be seeing it as, “I gave a clear no, he agreed, then when he was angry he crossed it anyway.” That is why screenshots and explanations may not land right now. Trust usually comes back through repeated behaviour, not a better argument.
I also say this gently. The spiteful urge is the thing to take seriously. Whether the label is BPD, ASPD traits, trauma, impulse control, or something else, the pattern still needs a plan. When that urge hits, you need a rule that is already decided before you are angry. Something like, “I do not touch social media when I am activated. I put the phone down. I leave the room. I write the urge down. I wait until tomorrow before I act.” Not because you are a bad person, but because your angry brain is making decisions your calm brain has to clean up later.
With your stepson, it may also help to make a clear parenting plan with your wife. Maybe when he is dysregulated, mum leads and you support from a bit of distance unless she asks you to step in. You might have meant to calm him, but if she read it as threatening, then it is worth changing the process so everyone feels safer, especially the child.
For the black and white thinking, DBT skills are probably the best search term to start with. Look up mindfulness, distress tolerance, emotional regulation and interpersonal effectiveness. Those are the skills that help with the gap between feeling something and acting on it. I would also ask your GP or psychiatrist about a proper DBT group or personality disorder focused therapy, because this is hard to fix with willpower alone.
For free or low cost starting points, have a look at Project Air, the Australian BPD Foundation, DBT skills worksheets online, and the Beyond Now safety planning app if you ever get into a crisis headspace. Apps can help, but they are not a substitute for therapy, accountability and a plan your wife can actually see you living by.
The biggest thing I would say is this. Do not make your wife responsible for recognising the good part of the mistake before you have fully owned the boundary breach. Start with, “I crossed a boundary. I understand why that hurt you. I am not asking you to trust me today. I am going to show you through actions.” Then do the actions, quietly and consistently.
I hope you keep going with help. The fact you can name the behaviour means there is something to work with.
