My horse was a only horse for a while when our other one passed away and you could really tell a difference in her attitude. She seemed depressed and was only really looking for attention. We had a goat already so we put her in with the horse and they got along so well. If we went on a trail ride the goat would sometimes come and tag along. We eventually got two other horses. One of the horses was fine but the other horse really abused the goat. We eventually had to separate them. So just keep an eye on them. The goats are really not expensive and can be really awesome pets. I would recommend trying to get one.
I'd definitely agree that if you can handle another animal then it would be a good idea. I've had a couple of friends who have goats with their horses and it seemed to work out pretty well. I checked all the goats out at the state fair which was fun and the owners were very helpful. I looked into getting one for my mare too and I liked the Oberhasli. They are super cute.
We recently found a new home for our mare. (that was sad, but she is perfect for what they want. She wasn't working out for what I wanted to do) I was worried about our yearling gelding, he was so attatched to her. I won't be looking to buy another horse I can ride until next year. And having just him gives me more time to work with him and get him doing a lot better with ground manners before taining next year. So we decided on a mini horse for company. We got one the same age as him, and my lord are they cute together! I think Bolt is estatic to have another young horse to play tag with. I don't have to spend the time on a mini like I would with another bigger horse. He is a good little guy for my little boys to learn some horse things with also, man was it cute when my 2yo was leading him around! He cracks me up when he runs too, those little legs going. The stud at the place I got him came charging at me to defend his little harem, and that was just cute also. Took him forever to get to me! Haha.
Anyway, just a plug for a mini companion. Maybe a little more work than a goat, and you do have to do their feet like any horse. But the cuteness makes up for the small added expense. We considered a goat as well, either would be better than your guy being alone.
So after searching the county for a mean enough goat, I found a perfect horse to keep Chip, my first horse, company! I think this will work out better than a goat. This is Sargent Pepper, if I loaded the picture correctly, a Paint Warmblood mix. We are so happy to add him to our four-legged family! He's totally bomb-proof broke for my husband and any people who visit us.
I'm sure I'll see a change in Chip for the better as soon as Sarge joins him on Saturday.