My DP is like this. He can't admit he's done something wrong. He won't say sorry, he'll reinvent reality instead. It's strange as it's at odds with the rest of his personality, which is genuinely kind and caring.
My cod psychology is this: DP has a self image that he's a good guy. (And he very much is, mostly). He has to maintain that image or he's a failure (in his own eyes). On the occasions I push it and said - no, actually you are in the wrong, and he's accepted that, it's then been accompanied by massive self-flagellation, which isn't at all helpful.
So, he's never been able to say, genuinely, "I'm sorry. I didn't mean to do that. Don't worry, I won't do it again", It's either some version of "I didn't do that" or "that didn't happen" or "it's not important" or just avoiding the conversation completely. OR it's "I'm sorry I'm such a useless c*, I'm totally worthless". It's infuriating as self flagellation is no use to me, and nowhere in this is any genuine self reflection or desire to make things better for me. I can understand why he avoids being in the wrong as it's so painful for him. But I don't understand why he can't see this and just learn to say "sorry I fucked up" and it be no big deal.
I'm starting to suspect it's something really deep seated as I can see my 6yo DD is the same, and has been from a very young age. I don't think it's learnt behaviour. She's terrified of being in the wrong. She can say sorry now, but it took a lot of work on my part - if she needed to apologise to someone she'd totally freak out and I'd have to talk her down until we could go apologise to them together, me holding her hand. That's helped as she can say sorry with only a bit of encouragement now. She still freaks if she does something wrong unexpectedly though. For example if she knocked over a chair and it hurt another child and she knew it was her fault, the child screaming the most would likely be my DD, not the hurt child. I've seen her sob uncontrollably when something like this has happened.
I'm working on helping DD with it. DP is as he is. He can't even talk about it as he sees that as criticism, which he does whatever he can to avoid, so we go in circles. I find it very frustrating and hard to deal with.
We have ASD in the family. I thought it was just from my side, but I'm starting to wonder if perhaps DP and DD have traits also.