I keep coming back to this because I think OP is pretty plucky (I mean this in a good way) and does actually want to improve their situation, despite some questionable statements upthread. So here’s a thought. OP, you said earlier that you have to get a perfect distance on your horse or he’ll stop, but this doesn’t really happen if you keep your leg on (if I’m paraphrasing correctly). I’m wondering if, in some ways, this idea of the “perfect” distance is actually contributing to the problem. The logic behind that:
A lot of people get so hung up on there being one perfect distance, and it causes a problem because they’re trying to aim for this one take-off spot at every fence. That puts a lot of pressure on you as the rider, and for some people, if they come off the turn and don’t see that one spot, they freeze, take their leg off, pull to try to make it happen, etc. Then if it doesn’t work out, there’s this negative feedback loop in your head of “oh, I didn’t get to the perfect distance, I’m not accurate, I’m not good enough,” and that can wreck your self-confidence. In actuality, there’s a range of distances that you can leave from, with the width of that range dependent on the horse’s scope. My trainer growing up had a great way of showing people this in lessons, but I can’t really do that here so please be patient with some poorly drawn stick art.
Let’s say the end of the ring is the bottom of the screen.
|===============| <- this is your jump
>>>>>>>x <-- hypothetical perfect distance (> just so your hypothetical distance is in the center)
So this is a lot of pressure on a rider to come off the turn and approach a fence aiming for this one little x. And what happens if you don’t get to that x? What if you’re a little long or a little deep? If you’re thinking about it as needing the perfect distance, that’s a lot riding on getting right to X marks the spot. But what it’s actually like is more like below:
There’s really a range for your horse, and he can jump from anywhere within here and clear it.
So what’s really key to getting from one side to the other? It’s not the perfect distance, it’s getting to a place within the horse’s range with enough impulsion and enough balance that you can be a little long or a little deep and still be okay. Getting to within that range can be summed up in 4 steps:
1.) Establishing a canter that has enough impulsion that you have options at the jump. I’m not talking about going fast, but about having enough canter that if you’re a little long or a little deep, your horse can still get from one side to the other.
2.) Establishing a track to the fence. It’s important to be straight. It’s really tough to find a distance you trust when your horse’s front end and back end are on 2 different tracks.
3.) Maintaining your pace and track to the fence. Once you come off the turn, you shouldn’t need to make big adjustments in stride or straightness (which isn’t to say there’s no adjusting going on, but you shouldn’t feel like you need to gun for a big distance or choke the horse down to nothing if it’s going to be deep).
4.) Jumping the jump 
I’d bet money that when you’re jumping around and it’s going well, you’re not getting to the same exact distance every single time, but you’re carrying enough impulsion and balance that you’re somewhere within this range and you’re confident that it’ll work. Your confidence gives the horse confidence. You know your horse best - maybe he really doesn’t like to get deep, so your range is a little smaller, or you need to support with your leg more at that spot, or maybe he’s weird and if you’re getting deep, you need to drop the contact - you and your trainer know his idiosyncrasies and your skill level.
I stand by everything I’ve said in this thread already, particularly regarding the importance of being physically strong and having a good foundation (and the benefit of reviewing videos of yourself), and I’m probably shouting into the wind with this post, but it was another thought. That could help. If you read it. And if my stick art actually posts looking the way it does in my preview box.