I don't think anyone can actually be "too attached." If you're insecurely attached then you're not attached enough because if you're attached enough then you don't feel insecure and clingy and worried about the relationship. I think people are at the highest level of attachment when the attachment is secure, but because it feels much more stable and less intense when they're not anxious and preoccupied, they may erroneously think they're less attached. It's a kind of paradox -- they're really less attached when they feel "too attached" because they haven't yet reached the level of secure attachment -- the insecure attachment is tenuous and fragile, like it always was for me until I finally felt securely attached to my T. I know now that I'm not any less attached to my T than I was when the attachment was insecure -- in fact, I am more attached to him now, but I no longer feel "too attached". I felt "too attached" for a very long time because I was anxious and clingy and preoccupied and sometimes very ambivalent about attachment. I wanted it but feared it and it was always on my mind, and it made me feel crazy until I finally felt secure. Now it doesn't make me feel crazy or anxious anymore and I don't feel desperately in need of his frequent attention in order to feel safely cared for within the limits of our relationship. If he and I hadn't spent so much time talking about attachment and unmet needs then I probably wouldn't have recognized these new feelings as secure attachment, and I guess I would probably see it as being "less attached" now because it feels less intense and much more calm and stable than it did previously. But when I felt "too attached" I often wanted to pull back to protect myself from the intensity of the feelings because I didn't know what secure attachment felt like, so I thought that if I was already "too attached" when I was insecurely attached then I'd be WAY too attached if I ever felt secure.
But now I know that's not how it works. Secure attachment is something that feels good but not overwhelming. It feels safe and it feels comfortable. I don't worry about being rejected for telling him something shameful and I know without a doubt that he will not get rid of me (unless he had to leave his practice for some reason) and it just feels calm and safe and good. The jealousy is gone, the need to be special is gone, and I don't feel threatened by disagreements between us anymore. When we don't see eye to eye it doesn't make me anxious; it doesn't make me think the relationship is over unless we always agree. It's hard to explain what it feels like but now that I've experienced it for the first time ever, it's awesome.