OK so I guess this is kinda venting but if anyone has any suggestions or guidance by all means!

I'm a guy been married for a longish time and not young. I don't really have any close friends just acquaintances. I am always to scared of rejection to really take a chance on making  a meaningful friendship on that level. I'm obviously close with my wife but that is different and a whole other kettle of fish. Point is even the closest friends I have had in my life I've been literally incapable of telling them anything about my feelings, thoughts, fears, dreams whatever. I have been in situations years ago with friends where I desperately wanted to open up and share and was fairly confident they would be receptive. I was sitting their not saying anything just keeping up a relaxed act while what I wanted to say was going round and round in my head almost screaming to get out but when I try to open my mouth I can't. It's not even a macho thing, I am fine with having feelings and if I'm in therapy group or otherwise I am able to spill deep dark thoughts and feelings but that's with strangers... like you guys I guess. So the only people in my life that I feel, remotely, comfortable talking to is my parent / siblings or my wife but I can't exactly share my thoughts and feelings about my relationship with my spouse and my family aren't objective and there's tension there so I gotta be careful what I say...

That's a conundrum because I'm recently diagnosed and all though I've been dealing with BPD my whole life I never knew it I just thought I was a guy with a short fuse and a tendency for depression and anxiety because I tended to overthink things and ruminate a little too much. Now I have this diagnosis and it doesn't change anything but it also changes everything. I used to be very sure of myself (most of the time) to the point of arrogance. I would speak with authority on anything and I knew that when my wife and I were having an argument I was fairly objective and my main problem was that I couldn't control my frustration and became too angry and spiteful when I was upset. Sometimes I would get to caught up on the small stuff and when I realized I would try and be pragmatic and de-escelate. On the rare occasion I did realize I was in the wrong I would change my mind and correct my faulty assumptions. That's what I thought... now I know I have BPD. That means I have a black and white view of things and that I have a tendency to split on people and have irrational responses due to fear of real or imagined abandonment. What now? Am I always wrong? I know that's not right but, now, I also know, that my perceptions aren't always reliable. So I have to question everything. How the fuck do I rationally and objectively assess the validity of my subjective perception which my fucked up brain twists all around itself? I try to stick to facts but when a discussion or argument is about subjective opinions and emotional responses to disagreements their aren't a lot of facts. So now I don't know what to do...

Add to all of the above I've been a shitty husband; not all the time but more often than I have the right to have expected my wife to put up with and have done things that I am ashamed of and has hurt our relationship. That's on me and I own it and so that brings with it it's own set of issues where my wife is defensive and hyper alert. So, although it's my fault, she has her own twists on her perceptions of my actions and reactions. How do I navigate a disagreement is it always my fault now? I feel like when we argue now I really really rack my brain to try and figure out what happened, what did I do? I try to explain myself clearly and make it clear I am trying to take responsibility for my actions and I need her help understanding what I can do to try and avoid a disagreement turning into an argument. Sometimes it works but sometimes it just makes it worse. I feel like I am caught in an undertow and the harder I try to swim back to shore the further away I get. I don't know if i am overreacting and am just being emotionally unstable or if my fears and thoughts are real and have a right to be addressed.

I started DBT therapy recently and I try to bring these things to therapy but by then the moment has passed and I'm not in that emotional space anymore. What ever subjective perception I had at the time is now set and my mind has already started to rationalize exactly what happened and categorized it and now I can't be subjective any more because it is locked away and 'solved' but not really.

I just feel so alone, empty and confused