Go ahead and find a different therapist. Often it's necessary to go to many different therapists before we find "the one" who ultimately helps us the most.

You have admitted you aren't getting any better. That's what therapy is about, the getting better so the relationship as "good" as it is is not a therapy relationship. Go ahead and move on to the next step.

It's a little like leaving home and parents, leaving a therapist/moving on. I had to leave my therapist I'd been seeing for 9 years because I was changing jobs and moving and was going to be too far away. You can't make a life around just one person; have to have yourself in order, yourself is all you'll have for the life you live; you'll always be with you but no one else can be. Getting use to the changes and growth life requires of us is a good thing. It will work out, you'll see.

P.S. 10 years after I left that therapist I was able to see her again and enter into therapy with her again and everything turned out great. One can't know what the future is going to bring and getting a lot of different experiences with different people, etc. is a good idea, I think.