Are you sure he received the anniversary email? I've had times where I've either sent or been sent something and it's gone missing or into a spam folder etc, even when other stuff to or from the same address was ok. If he usually would reply and now he doesn't, and you have examples of that I would have spoken to him about it before deciding to leave a process that has been working well for me.

You spoke of stuffing the hurt down to try and retain what kindness you can get from him bit therapy is exactly the place to try not doing that, to be open and clear about what you need and what you see has changed. I very much doubt you've broken either of your therapists but difficult interactions can leave you feeling you've done something wrong. I wonder if either he's not receiving your emails or if something is happening in his personal life that is taking time and emotion away from him work.

You're well within your rights to walk away if that's what you feel is right for you but I know I'd try to speak to him beforehand in case wires were crossed.