You did right.
When you think about taking on a horse like you had shown to us? You really and truly do not know what is going on with horse. And getting a GOOD equine vet's opinion can run into some money too.
Most horses, knock on wood, are little major expense after the buying of them, that is only board/feed and normal expenses monthly.
But if one gets sick? Then you are in major money. And a chronic illness, or one that will not resolve itself with some time? Major money.
Also, if you are going to have to board a horse with issues? You need to keep in mind that unless you are paying for separate pasture? You will have to put horse in with others that may beat your horse up, because he can't get away from them easily.
And even if you do pay for separate pasture, you can end up with BO deciding to put another horse in there anyway.
Horses make me a better person.