Perhaps you would have a friend with a farm, barn, pasture, even if a distance from you. You could at least rent a spot for your not rideable horses, and then have some funds to still ride.
As someone whose first horse has become more and more "pasture ornament" and less "riding buddy," I can tell you that enthusiasm will wax and wane. During the wane times, I find other activities to enjoy with my equine pal so that I still feel connected - my enthusiasm relies on him, not riding. We take walks to find greener grass, I groom him (for my own relaxation and his!), and I have picnics in the pasture while he grazes. Is it the excitement of blazing or meandering down a trail? Maybe not, but for me, its about the relationship. When I get the riding itch, I hop on and away we go! Continue looking for riding opportunities, but make time for your friend. The relationship doesn't have to wither because the ride time did!
I personally don't own my horse (and am currently looking to lease one). The school at which I ride doesn't have anymore riding lessons on the days I'm free so I can only squeeze in the occasional ride/lesson. Honestly the gap between some rides can be a bit off-putting but I think hanging on to riding is better :) One way you can keep up your enthusiasm might be to hang out with horses more? Or just read/mentally go through riding stuff.
What about teaching him tricks using clicker training; the relationship that develops when using R+ training is amazing and you can see your horses true personality come out.
I spent the last two years looking for another riding horse when my pony developed navicular syndrome. I discovered in that time that I actually was able to take a breather from horses. I enjoyed it too. Sometimes it's best to just step back and take a break, even if it is for two years!
One more thing...I spent my time reading about horses and watching my neighbors' horses at pasture.:)
I lost my old mare after being together for 23 years…. only a month ago…. I hadn't ridden her for 12months, due to medical issues for her. I have 7 other horses/ponies…… but I've lost that "must ride" enthusiasm…. Love all my other Neddies, but they are not "My Old Girl" who saw me through a lot of life challenges ( for me, maybe not challenges for others) I run a small riding school for Beginner & Nervous Riders… it is just me and my Neddies, and helping and teaching is fine. Looking after my Neddies is fine, I just feel…. I don't want to ride! It is hard…….
My quarter horse mare impaled herself under her right armpit with a tpost, in2013. Her rehab was 11 months. We had 3 other horses plus a colt. Our gelding was my mares rehab roommate, I started riding our broodmare. As my mare was rehabilitating I did ground work with her groomed her everyday and our bond now is stronger than ever. Just because a horse has a medical issue and cannot be rode dosent mean we have to stop training. Teach a horse. tricks, work and lateral bending, teach how to bow, pedastol work, even setting up a trail course with things laying around. Logs, tarps, swimming pool noodles, etc. Desensitize your horse to things that may or may not be scary. Trust building exercises are the best way to establish a bond stronger than just riding.
Scrabble around for the occasional ride. Lots of people have horses and don't have the time to give them the necessary exercise or attention they deserve. I am sure you could find someone willing to let you ride their horse once/twice a week. You don't want to lose your riding strength and muscle, especially if it's a long break. You might never get back to riding again! If you're up for the challenge of riding under these circumstances you won't regret it. So sorry about your own horse.
2 years ago, my 23 yo OTTB became lame and my husband and I began to share his horse that became my horse. Turns out, my husband knew before I did that my horse would soon become a pasture pet and got his horse with the full intention of him being mine. I still can ride my 23 year old horse on easy rides late spring, cooler summer days and Fall and I still graze him. I get strange looks from bikers in the park when we're just hiking through the trails together. Sometimes, people ask about him and sometimes I joke and say, he's really an oversized Great Dane (he's 16.3). We now half lease a horse more suitable for my husband. the lady that owns the horse doesn't have time to ride and wasn't ready to sell. So, now we just share the costs. I belong to a adult pony club and I'm amazed at the amount of horse sharing there. It's really a special group of people. Watch the ads on Craigslist or even the local equine advertisement.