Long time lessee

I need opinions on my situation. I returned to riding about 6 years ago with a former riding instructor from my youth (I’m now 50). To begin with it’s been great as I ride with several friends who also lease their horses off him and it’s been mainly a positive experience for us all and I’ve managed to get back and improve my riding I think to an even better stage than previously when I owned and competed my horses. These days my primary focus is on dressage and the horse I have ended up with is reasonably good at this as he is a nice schoolmaster type.

My issue is that our instructor is good at what he does (instructing) and has rebuilt his business up in the last couple of years after it went through a bad patch when he fell out with his last business partner. We supported him during this time with our leases so he could continue to pay his bills etc. However of late we have noticed a shift in his attitude towards us. I found out he has been using my horse and a couple of others for the odd lesson as he’s been getting really busy and is short of horses. He did ask me initially several times which I didn’t mind but then then it became obvious that my horse was gtg used more than the asking was occurring. I’ve been paying a full lease and have not been that happy about this so I questioned him about it. He said he’s getting really busy and needs to use my horse. So we discussed this and agreed we would split the expenses he cud use him for the odd lesson. Then I find out through the grapevine that he has part leased my horse to another lady! I was shocked as he didn’t discuss this situation with me and has just assumed that I’d be ok with it.

However upon questioning him he said she’s a nice lady and doesn’t want to compete etc and will just ride at my place (we go down the road to a big equestrian park) for our lessons. I am still the main lessee and you are just to share the expenses. He has not put this in writing as is quite useless in this way! Which I feel a bit uneasy about as their could be some issues in the future. I have met with this woman as she approached my friend who told her our situation. I have written to her in a semi formal email explaining what my lease has been and how it could work out between us moving forward offering her to give me some feedback of what her requirements might be etc. I do feel under the circumstances I’ve been very fair!

Although I’m a little annoyed that this took place without any real discussions between us all. Although he does own the horse and I guess I’d rather have one other person involved that I know about. I’m
trying not to feel threatened as I’ve grown to love this horse so much. I guess as long as we can agree on the finer details it might work out ok. I also realise I’d be hard pressed to find another horse as good as him to compete on unless I spent a lot of my own money etc. My kids are still in college for another year or so then my husband and I may start to travel a bit in the future. So I could possibly only ride for another year or two and don’t want the responsibility of full horse ownership for this reason and also I live in town so would have to board my horse somewhere which would be even more expense.

I’m just planning to carry on for now and see how it all works out she does seem nice but I also don’t want to get too friendly either or lose the control I’ve had as although she can ride I’m at a different level altogether. I guess it’s more about the money to him but has made me feel a bit vulnerable.

Thoughts on how to handle this situation moving forward would be helpful.