Aaaah...it's like saying if we'd known how difficult it would be to have children, we wouldn't have gone into it.
Probably true, but also beside the point. Well, I did know how difficult it would be to have kids, and so I didn't go into it, and I was right about all of that...but the point is, if you want kids, or you want to be a rider, finding out that it's going to be difficult doesn't usually change that desire.
IMO, the most valuable thing a person can bring to a relationship with a horse is patience. Patience with yourself, patience with the horse, patience with the process. It's a journey. There isn't some point where you will "know" how to ride. There will always be things to learn, and people to learn from. There isn't some point where the horse will *always* behave and do exactly what you want...any more than there is a point where your kid will "always" behave and do exactly what you want. The key is to develop a relationship and to do training (and you will see people say it here: every time you interact with a horse, you are training it, and that is oh-so-very-true), and to do the kind of training that results in a horse that will mostly behave and usually do exactly what you want.
You're getting trained too, and what you'll find is that at those times when the horse isn't behaving, you have a bigger and bigger toolbox of responses you can provide, and the bigger that toolbox is, the more likely it is to hold a tool that works.
Another valuable trait a rider can cultivate is the beginner mentality. If you always think of yourself as a beginner, you won't develop expectations about where you "ought" to be in terms of progress, and it's less likely - if you don't have those mental benchmarks - that you'll get frustrated and lose patience with yourself, the horse, or the process.
Keep trying with the bridle trick. It will work, eventually. Stick with it, and this time next year, someone is going to resurrect this then-ancient post and give you some advice, and you're going to get the notification and think "Huh? I had problems with tacking up the bridle? Oh, yeah, I guess I did..." Is also true about the rest of the stuff that is causing your disturbance right now. A year from now, you will NOT be having THESE issues. They will be totally gone...and replaced with some new issues. Can't get the horse into a trot now? By next year, you'll be on a horse that wants to trot too much, or a horse that doesn't bend, or a horse that has been refusing jumps, etc etc etc. It's a process - got to let it unfold. And be patient with yourself.