Wow.

I know every feeling you described. I feel the exact same way about my T. I never got to attach to any parental figures and didn't really attach to my spouse.
I have resisted attachment to my T and go back and forth distancing myself from her. Currently, I am growing closer to her because I've never felt such happiness and affection before. However, it is somewhat overshadowed with the fact that I know I will suffer a great amount of pain over allowing myself this temporary happiness. The fact of the matter is that I'm more used to dealing with rejection and pain and it will just be par for the course anyway, inevitable. I'm not accustomed to feeling cared about and attached. For now, I I'm willing to enjoy what she's offered. I don't know how long I'll be willing to do this. I don't know how healthy it is for me to embrace this temporary attachment. I just know that I want it right now.
I fully respect and understand your being in a different place then I am. I have even been where you are. I know that pain we'll and it's all consuming. My only advice is to be brave, hang in there and be kind to yourself! You are not alone.