Oh Mabel, no, I would never roll my eyes like that! I have been in a very similar place myself, and if you are anything like me, your own self-punishing thoughts will make you feel worse than anything anyone else can say here. I wouldn't dream of adding to that. I am just sorry that you are going through this painful time.
I'm not one who has no sympathy for someone with a hangover just because it was self-inflicted.
I think that it's fruitless to think of yourself badly for falling for someone who signs their emails 'peace out'. The truth is that every single one of us is a mixture of the sublime and the ridiculous. We look at those we love through loving eyes, and therefore (ideally) we accept them as they are, daftness and all.
Obviously a couple of things have changed - his need to present himself in the best light to you, and your willingness to see him through loving eyes.
It's a hard, hard wake-up call, but it's the start of coming out of the state of heady, dizzy highs and crashing lows that you have been going through.
I remember that feeling of coming out of it like coming out of a sort of all-consuming drug-induced haze. It was like having a very very cold shower and shaking the droplets off and gasping and hating it and yet suspecting that a huge sense of relief was there as well.
You were talking about your DPs explanation of his freak-outs. I think it is very interesting and fairly insightful of him to describe it so visually and identify an early memory of that behaviour.
I do think that in describing walking along with his mum like that, he was actually describing another symptom of his fears, rather than the cause. Perhaps he needs to explore that in counselling or in some contemplation/reading of his own. Perhaps not. Either way, that is HIS story. He is not justified in making it your burden.
Just to make myself clear - I think it is good that he has expressed these memories and been searching for explanations. But those are ultimately just words to express his feelings. What counts now is what he DOES about his realisations and discoveries.
If he carries on just the same as before without attempting to heal/mend/address his inner fears, then all that he has effectively DONE is to put pressure on you to accept his behaviour because it has its roots in his childhood.
You are not there to carry his personal burdens. You are his friend, support and partner. That means you help him to carry his own burdens - you enable him to feel stronger and braver.
You obviously care about him very much indeed, and your instinct has been to help him, reassure him, support him.
Perhaps the best way of supporting him now is to point him in the direction of something that will help him to take responsibility for his own behaviour? I think this would be something that would do him a lot of good in the long run, although it may be hard in the short term.
You know him best. You know whether that means counselling, internet reading, book reading, a thought diary . . . whatever route he takes, he has to take a route. He has been stuck in that place on the pavement, waiting for his mother to turn around, for too long.
Using his image, I think that he needs to go back to that pavement as an adult, take his old self by the hand and start walking along again. He is the only one who can do that. Trying to make you do it CANNOT work.
I hope that this is coming across in an understandable form - I have had a couple of very clear experiences in my life where I did exactly that - went back to the child I was and realised that I could help her/protect her myself. Very healing. But I realise it may sound like crazy talk to someone of a different character!
(I come from a very 'alternative' town where this kind of thing is the normal level of conversation overheard in cafes etc, so I do realise it may not make sense to everyone. Feel free to roll YOUR eyes!)