I don't know if this will answer your questions to some extent but it might help. 15 years ago (and yet I still remember it pretty clearly) my fiancé buggered off to be with another woman, after 11years together (we started going out when I was 17, he was 19) - so a familiar time frame to some of you.
I was desperate to find out what I had done, why he had changed, why he didn't love me any more, what she had that I didn't, WTF HAD HAPPENED?? He had no answers. But I kept pushing and pushing, so he made some up. Admittedly, there may have been partial truth in them and that was what did the real damage to me - it took years and quite a lot of therapy to shift the negative impact of what he eventually answered - that I was "impossible to live with", that I was "too temperamental", "too independent" etc. etc. Oh yes, and that I didn't like his family - well that was only true as far as his mum went, the rest of them were ok!
In the end, one of my counsellors gave me the first helping hand - it didn't matter what I had done/hadn't done, was like etc. - what mattered was that he didn't love me enough. It was his failure, not mine. Ooh, that made a difference! First step, lots of others after, mostly relevant to me personally (low self esteem, family issues etc.)
The other thing that might help is what I got from a client of mine - he said that when things reached a level where he was unhappy, he would start to withdraw and compartmentalise. So, he could quite easily hurt his previously-beloved because she had been moved from the "loved" area to the "not loved" area in his brain. Thus anything that involved her trying to re-access the "loved" area simply didn't work for him, so he ignored it or rebuffed it.
Some men, in particular, can become quite spectacularly selfish when breakups are going on (don't get me wrong, some women can be too) and they will do almost anything to avoid feeling bad themselves. Guilt makes them feel bad, so they try to remove guilt in various ways, including re-writing their personal history so that it somehow becomes the woman's fault, or that they never really loved her that much anyway and were just being nice/polite etc. Thus, crying just gets on their nerves totally because it ignites a spark of guilt => they feel bad => they try to stop feeling bad => they turn it back on you and make it your fault in some way.
I think the only way I ended up dealing with what had happened and why was to agree with the first counsellor - he just didn't love me enough and then he lied to make himself feel better and to shut me up. Pushing for answers that they can't vocalise/probably don't even have themselves can be extremely counterproductive if they are backed into making something up, so let it go.You never really know who they are anyway - they adapt themselves to your expectations to some extent, and when they no longer care about your expectations, hitherto hidden and unexpected aspects of their character might come forward. They've always been there, they were just hidden because they didn't "fit" into your relationship; but it does feel as though the person has completely changed (usually into someone we wouldn't have spent the last decade+ with!)
Work on the principle that they don't love you enough, that you don't want to be with someone who doesn't love you enough anyway and that someone will come along who DOES love you enough, even if it might take a while. It took a few years for me to find DH but it was worth it.
((hugs)) to you all and I hope you find your way through - it's a horrible time but you will come out of it better and stronger, knowing who you are and that you can manage without them.
Oh yes, and smile at yourself every morning in the mirror - it will make you feel better, honestly.