I agree that attachment can be healthy and attachment towards a T of whatever variety can help you understand how you attach to other important people in your life, or understand where you're missing something from them.

I have a pretty secure attachment to my T, although I do think I can still be avoidant at times and once when I decided to take a summer long break, it was painful as I left the office after my announcement. I went back the next week, or maybe the week after, and whatever it was, it was more because of my pride than because of what I truly wanted (take me back!).

I tend to think I will continue therapy with another therapist when my T likely retires in a few years, or if I move away from this community. In the not too distant future I will do every other week with the idea of moving to once/month eventually as a way to continue the self care that therapy helps me keep on top of. I'm not dependent on my therapist or therapy, but there are things about the kind of stress I face in my life that makes therapy useful for me.