It won't be that simple. First of all, it will be a miracle to find anyone on earth who will let you near their animals knowing what your intentions are. And then if, IF you ever get close enough to a horse you're never going to know if you two will get along. If your personalities will gel. Animals to a large extent are like people, looking for a partner isn't like going up to the nearest one and saying: "hmmmm, yes you'll do." You have to build up a relationship and trust.
It will be much safer and easier if you own a ranch or your own big property where you can keep your own horses. Even then, there's no guarantee that it will result in your dream fuck buddy. Sometimes it's best to be patient and rather take the safe route.