No. I do not think you have to be attached for therapy to be useful.

This is such a tough question to answer. I think if someone were seeing a T for, say, drug addiction or sexual dysfunction, attachment would be unnecessary. However, for people who were hurt in childhood and have attachment issues as a result...perhaps attachment to the T isn't completely necessary for healing, but it's probably going to come up. In that case, I think the necessity of attachment will depend on what the person in therapy needs to work through.

I will say this, though: awareness of feelings doesn't always mean you'll be able to avoid or control them in the future. Therapy is an intense experience that requires trust and a good emotional connection between therapist and client. If attachment has come up for you before, it will probably surface again, with or without your consent. (Sorry.)

Attachment issues are very painful, so I empathize with you wanting to avoid them. (If I had a nickle for every time I felt humiliated in front of my T...Ha!) But working through this stuff is important for those of us who were hurt in childhood. It's just part of the landscape. What I would do in your shoes is find an experienced T who is comfortable with attachment and willing to work with you long-term in case it does come up for you again.