erinaceous - thank you. I'm sorry you weren't through this too.
Beau - I think this: there's no point looking back - you can learn lessons from the past and you can use them to change the future is a very good point, and I guess in trying to understand what happened and why, to try and learn those lessons. It's pretty hard work.
Sparkle - I think it's interesting to think about how it could have been, and recognise that that might not have been all chocolate sprinkles and flowers either. Thank you.
Parsley, I think it experience sounds very similar. Thanks for offering to PM. I'm very glad you managed to make good moves and it heartens me!
Margie - I guess that's what I'm trying to do, in a way - think about the future. It might not be super-obvious from my thread, but I really do spend most of my life thinking about the future, working for my qualifications so I can move on to the next step, doing what i can to work on the problems I still have, with therapy and mood-stabilisers and (attempts at) healthy lifestyle changes. I think looking at the past is a part of that; I hadn't really thought much about my past, or my future, for years, except to berate myself and regret what I've done with my life up until recently. I'm now mostly looking towards the future, not dwelling on the past, but I did want to get others' input on this particular thing.
Haybale - you sounds like a great, caring patent! I hope nothing like this ever happened for your family but i think you will make whatever choices you do based on wanting the best for your children (as I believe mine did). I'm doing some counselling (planning to finish soon, partly due financial reasons, as although all my NHS team believe I need psychological input, it's not available for me) at the moment, which has really helped, and is probably partly what has provoked this reflection.
music - I promise you, I really don't focus on my parents as the locus of blame! I agree it's not good to dwell on it too much. I thought the relationships board was probably the best place to discuss this particular small part of what I'm trying to make sense of currently, and have had lots of useful feedback from you all to help me contextualise this part of my story. I'm under the GP and get checked by the CMHT to help me manage my mood disorder at the moment, so you're right, treatment for the mental health problems is a vital part of all this kind of stuff.
bran I know, I really should talk to them, I agree
I just really don't want to upset them, or make them think I blame them for what happened. I really don't. I don't know whether they feel they might have made the wrong choice. I tried to talk with them the other day about things that happened at school, but my dad was keen to say it was water under the bridge, though we did talk about what happened with school to a certain extent.
Thumb - lots of ASD traits in my immediate family (two of whom I believe would almost certainly get a diagnosis were they to request assessment - they're way Aspie compared to me!). You're right, it's so hard to unweave what's ASD, what's mental health, what's environmental, and what's just bad fucking luck
I don't think it's necessarily more complex - judging by how many people say they have something similar in their past and that people on the Teenagers board have similar issues, it seems like a common enough thing, ASD or not. That's why I didn't mention it or think it might be relevant in my OP - I guess consensus here is that it is relevant? My counsellor is a psychologist who specialises in ASD and I am part of several supportive and social groups online. I agree, it helps to know these things about yourself and find people who get it.
Cab - that sounds like a horrible experience, but I'm guessing you feel like it's part of what's made you who you are now? Apologies if I've got that totally wrong. I don't really want to leave him... I don't feel he's controlling.
cant - thank you so much for your good wishes for the future.
MrsJayy - I guess what in working through at the moment is whether I do want to leave him - I can't imagine how i could, at the moment, but I suppose I'll cross that bridge when I come to it
Thanks 
Granny, I was kept in hospital under threat of section when I was a teen - you're right, it's a bit drastic 
irregular - thanks for the view of confidence! :)
Roomba that's sounds awful for her :( and for you, too. These things triple through families - it's part of why I feel so guilty about it all, I guess. I'm lucky in that my parents aren't toxic at all - they've always let me know that they love me and I have absolutely no doubt they'd take me in any time I needed it.
category - ASD and a mood disorder.
Tinkly - DP has been my biggest cheerleader and supporter in my efforts to get the qualifications I need and to help me in getting to university. Admittedly he wasn't keen on my living away, and still talks about moving house, but I think he's coming round to the idea that I want to try living on my own and to concentrate on my studies for a few years.
Giddy - I think you're right - it's only now I'm far advanced in years and decrepitude that I've realised ALL the adults are just pretending to be grown-ups… 
Sandy - I do wonder. I think this thread has been good because I've been able to get a wider set of opinions on why they might have acted the way they did. I've never doubted their intentions, just had trouble trying to work out all the whys and wherefores in my head. My parents knew his age - he'd been to my house once before, and picked me up from home in his car to take me to his place, about four hours away.
Zaurak - I really am genuinely awful at cooking! I'm not too sad at, say, baking, where there's an explicit set of instructions I can work through one at a time, no points at which I have to calculate and manage several factors simultaneously, and no variables that can go wrong. But give me stew and baked potatoes to do and my brain becomes a tangled mess of confusion and panic
I'd have to live on freezer pizza… DP isn't the one who says I'm no good at things. He encourages me to try, but easy things like chicken breasts and sauce so I can practice with the easy things, etc. And he believes I'm capable of far more than I do. I think I lack confidence a lot, and - well, he already has the skills so it's easier all round if he just keeps doing those things
He did teach me how to use the washer-dryer, and it now has a sticky label with each step in the sequence clearly laid out for me 
memyself - I have lots of joy! Have you ever experienced hypomania?
But I do want to change things, and u think they are changing, gradually.
whambam, that sounds awful :(
coco, that sounds really tough 
Trilit - I really hope things turn around for son soon. You must be so worried and sad. Thank you for the good luck wishes.
Peachy - ASD + MH problems is a right bugger of a combination isn't it? I'm so sorry you missed out on your career. Is it something you could go back to (or maybe something related)?
mamia - I don't think I really see him as either a sexual partner (not any more) or as a parent - he's now like a really really good flatmate if you know what I mean. The house is in his name. I assume if he died it would go to his parents. He deals with all my money because I have savings (which he doesn't). I don't feel groomed - I feel I was groomed by another man before him (and grooming was known about and covered in the media when I was sixteen - I remember thinking at the time about grooming and deciding I definitely wasn't being, by either of them
)
I'm sorry I haven't been able to fully answer everyone, and how I haven't missed anything - this is really long as it is 
Also sorry for all the typos! and thanks to all of you.