Orange, I see you often ask questions as to why the WAS is the way they are.
Sometimes there are no explanation, sometimes it's really a lot of speculation.
I do know even if you come to a likely answer, it really won't change a darned thing.
I know, because I became obsessed with trying to figure out how my ex could be such an awful person, how he can totally lack remorse. There area bunch of different possibilities, neither of which truly make a difference. I just knew I had to be ok with the person I am, not the person he is.
Of course, going forward, I look out for red flags and try not to ignore them, but even if I find them in a potential partner, I don't need to understand the "why". They are there no matter the reason.