I had an abusive upbringing and was a ball of internal rage until I was about 35. What helped me was talking about it. I just needed someone objective to calmly confirm what happened wasn’t proportionate, normal or healthy and in some cases, broke the law.
My parents think they did a great job. They believe they’re soul-mates (maybe they are). They’re very critical of us if we show flaws or fail. They minimise, like ‘we were maybe a bit strict’ or ‘oh we’ve had our differences.’ As in, the time my father punched me in the face age seven and split my lip, or the day he back-handed my mother so hard he broke her eye socket, perhaps. I felt as I grew up like I was going mad.
They needed help themselves, both were victims too. As I got older I blamed her for letting it happen but now I see why it worked out like it did between them and I feel sorrow for both of them. I don’t think they were equipped to realise how far from okay it all was. They could both be ‘abusive childhood’ case studies themselves.
My siblings have varying degrees of anxiety and one has been diagnosed with cptsd. All of our lives have been shaped by abuse but none of us are abusers. None of us can readily feel joy or excitement, it’s like our brains just don’t register positive emotions, we need to try to be happy. I’ve had suicidal ideation and so has my oldest brother. We are hyper-vigilant and one of us in particular has serious problems with self-control and empathy. However, he doesn’t have kids as a conscious choice.
I was the first one to realise I couldn’t carry on blaming my parents for my state of mind. They caused me damage, yes, but it was my responsibility to get my head right. A 40 y.o blaming their parents is making excuses, in my view. My father still blames his father for his own traumatic childhood and one is long gone and the other is a very old man. We only get one life, we need to accept what we can’t change and face our own demons. I wish I’d come to the realisation much much sooner. I wish I’d grown up in the internet age where I could have accessed help and information.
I really hope this isn’t going to cause you offence because they’re your child and you clearly love them and I’m sure they’re a nice person in many ways, but abusing you and flipping out if they meet opposition might not be solely down to being an abuse victim; I don’t want to say ‘narcissist’ because it’s so misused it’s basically become meaningless now and anyway I’m not qualified to diagnose anyone. But personality disorders can be caused by childhood trauma, I think?
It may not be that, only that they’re a troubled person who right now is not coping with what’s happened to them, I can’t judge, I don’t know the facts, I’m no expert and am only speaking from personal experience. But I do hear alarm bells in ‘abusive to my parent’ and ‘quite happy unless I don’t get my way/things go wrong.’ If anything I am more comfortable when people are treating me like shit and I get wary when things are going my way - admittedly that’s not normal either.
On a practical level I don’t think you should continually give in to them ‘just in case’ either way. It sounds like you’re being manipulated. Do they still threaten suicide now or is it that the fear of it has never left you? What triggered the previous attempts?
They’ve had therapy, they’re on medication. Have you also had trauma-informed therapy? Could someone qualified help you to learn strategies to interact effectively with a traumatised adult DC who exhibits abusive behaviour? Presumably you were with an abusive partner? And then had your shared child go through a lot? Who helped you? Do you carry guilt? Does DC feel anger because you ‘let it happen’? Are they educated, as an adult, on the challenges the ‘other parent’ faces in these situations? Apologies if any of this is wide of the mark.
Tantrums absolutely can be a response to trauma, I’ve seen them since I was three years old - and I’ve thrown them. I had a hair-trigger temper when I was younger, so do my siblings. Now I have cast-iron strategies, because I have kids, I don’t want to be my parents. I learned how to parent from my best friend’s parents, I had to construct a model for myself. Clearly my DH was here too so I wasn’t making all my decisions alone.
To your DC, holding the threat of suicide over people, going postal when you don’t get your way, can’t be condoned and shouldn’t go unchallenged, regardless of why it’s come to be a person’s coping strategy. They cannot always get what they want, can’t always hear the words that please them. Look at the misery caused on here by marriages with people who must always have their way.
You sort of imply that if DC’s partner saw the worst of it they might well change their mind about their relationship with your DC. If DC can not do the harmful behaviour for the time they’re around - does that indicate they know it’s not right and some of it is a choice, perhaps? Perhaps you’re their ‘safe person’ but still, it’s not good for them to react like that for the own sake.
I am guessing but I think the way forward might take the form of calmly addressing the effect their conduct has on you and not capitulating. How you do handle it is a balancing act, since you feel afraid of what they’ll do and also feel a lot of responsibility. That might be rightly felt or misplaced. Their problems may not be fixable by you but I hope someone will be along soon with more expert advice and resources.