Sorry to hear you are feeling like that 
First things first, is your boy physically OK? Tripping and bolting would scream pain issue to me, especially if it was a true blind bolt rather than a pissing off... At his age and having worked pretty hard over his life I'd be surprised if he doesn't have a few nagging issues even if he is sound to the eye? Have you had the vet out for a full MOT, his saddle fit checked, physio, dentist? I know it sounds awful using your DH as a 'crash test dummy' (maybe wait til after COVID!) but if you can capture some of his bad behaviour on video to show the professionals that might help.
I have had confidence issues over the years as I think many riders do, although probably not to the extent you are talking about. I think they are overcome-able but you need the right background circumstances as well as the desire to work quite hard yourself at it, by 'background circumstances' I mainly mean the right instructor that really gets confidence and how to build it - they certainly don't all! They have to know when to push and when to back off etc. You also need good understanding personal support, some achievable but stretching goals and the right horse as well. I have to say I think I might question whether this horse is the right one for you (if he is sound and this is just how he is)? You don't say what you bought him for, ie are you wanting to BE/compete yourself at a reasonable level or were you wanting more of a fun all rounder? Unfortunately with well-bred competition horses that have been used to near daily hard work at a high level, however much their bodies might be ready for a step back and an easier time/lower level competition, their minds aren't always. And if they have always been ridden by pros it takes some adjusting to get used to an amateur - nothing to do with your skill level but a lot of pros, especially men (political incorrectness alert) ride in a forceful/dominant style which most amateurs (especially women!) don't and the horse can be left puzzled or just constantly pushing the boundaries.
And also, some horses just don't click with some riders. I occasionally sit on my friends lovely teenage warmblood dressage schoolmaster, he's wonderful to ride when going well which he always does for her, but if he was my horse I'd be a quivering wreck by the end of a week because although he's probably no spookier overall than my mare who also has her 'issues', he is so big and powerful that when he does do a little sideways leap or sudden snort and prance it feels enormous. Plus he is the kind of horse you have to ride exactly correctly, he does not respond well to being asked a muddled question or pushed when he doesn't understand what you are asking for, nappiness and spinning around are his go to but if he was a pisser-offer instead like my mare is, and perhaps your boy too, he'd be frankly terrifying. So if this horse is not the one for you then I think there's no shame whatsoever in admitting it and changing to a horse you do enjoy riding, its an expensive hobby at the end of the day and life is too short to be miserable. Don't worry about what others think, liveries will always find something to judge/gossip about so that's just something you have to live with! And as for 'letting him down', that's just silly, the horse only cares that he gets his grub and somewhere nice to live, he has no concept whatsoever of being 'wasted' 
Overall, I think I'd give him a little break while COVID is ongoing and your work is so stressful, maybe just get the yard to lunge or hand walk him if you don't want him losing too much fitness, but take the pressure off yourself completely. Then when you can, get all the pros to look at him. Then if all OK maybe get your NLP and some intensive support from an instructor you trust, and if things just aren't improving consider swapping for a different horse?