I know exactly how you feel. Kay stays at my MIL, which is about a half hour away. When I go during the week, I have time to clean her stall and groom then MIL always has some other job she wants help with or an errand she needs run. I've considered moving Kay closer but would have to pay boarding and the only boarding stable close have the attitude of "it's our barn, so your horse is ours too!" I know she's happy where she is. However the only time I get to spend with her and ride is on the weekends when my husband is there and can divert his Mom. The only problem there is HE doesn't get to enjoy the horses or help me if I need it.
Good Luck, I know it's a tough decision.
Horses are the guarding angels of the soul.