Hi, I have MS, I’ve had it for a long time.
MS severely limits my riding. I do not have much endurance so I can only ride 30 minutes at a time or I rapidly become ineffective in the saddle.
It also affects my balance front and back, and side to side.
My hand tremors can limit me using a bit though I finally found some bits that did not bother the horses too much (unfortunately these bits, Wellep, are no longer made). Before the Wellep bit all three horses I ride would emphatically tell me that I needed to go bitless when the weather got hot and muggy.
In the heat my lower legs get more unstable. Before I found the Spursuader spurs my riding teacher would march out and take off my spurs, usually on the first hot day of the year. This made riding a lot more tiring since I had to use my legs so much more. Since I have so little energy it can sometimes be challenging to get the horses to move out at all.
The technical fabric hot weather shirts and riding tights are wonderful, my summer riding has really improved since I started wearing them.
It sounds like you live a full life, good for you! I used to too until the exhaustion from my MS overcame me. If you start to get really, really tired it can be a good idea to cut down on your activities because this is an exhaustion that cannot be overcome by getting more fit. I went into downward spirals of exhaustion several times before I was diagnosed and each time it took me a LONG time to recover when my body finally forced me to cut back on my activities.
But I was diagnosed 25 years ago and I am still riding horses, and I am convinced that riding horses is the only reason why I am still able to walk on my own two feet (plus canes.) I ended up in an electric wheelchair, I wore that wheelchair out, but because I got back into riding again I did not have to replace the electric wheelchair, or use my wheeled walker all the time.
Keep on riding, as far as I can see it is the best physical therapy for people with MS.