Is there a reason that you think your therapist will suddenly change boundaries? Did your T mention changing boundaries or have you noticed subtle changes? Or is it more of a general anxiety about it? It sounds like you have developed some trust with this T and that can cause some vulnerabilities. I wonder if some of the fear is coming from the vulnerable part that trusts your T but perhaps is scared to? I don't know if that fits, it's just what came to my mind. I hope that you can not be so afraid that your T will change boundaries.