Help please cat keeps peeing on couch

My cat is overweight (has lost a pound and is continuing her diet) and has anal gland issues. I’ve taken her to the vet twice already to have her glands expressed. She pees on the couch whenever she has issues but it’s so frustrating because she uses the litter box like normal afterwards. I’m taking her to the vet again soon but i need other help. I don’t know what else to do.