I've been thru this same conflict in a major way, Rothfan. What I've learned from it is that I expect the end of therapy to be with the same kind of attached feelings as I started. That just seems so unbearable and also cruel of a therapist to send off a patient who is so desperately attached. But I'm learning that worrying about the end before I've hardly started is getting the cart before the horse, and just making myself suffer agony I don't need to. There's enough suffering in therapy without asking for some that might or might not be in the future.

I can get panicked about "the end" because of how devastated I will feel if it happens too soon. I'm severely, constantly, worried T will end before I'm ready, and not care that I'm feeling annihilated.

But what I'm realizing now is that there is a great middle part of therapy where I build a strong core foundation of mature strengths, through my close relationship with my T. I tell my T over and over all my fears, resentments, and experiences with loving and losing, over her and others. I learn all kinds of things about myself, and change about many things I've assumed about my childhood and family. I'm also soaking in the love and care of the T, an essential experience I missed in childhood. The circuits in my brain are even filling in what was missing about relating and loving in a good way. This going on through months and years of sessions.

When I'v'e gotten a huge pile of that relationship with T and myself, I realize that it provides a sort of cushion for enduring her vacations or stressful times with her. When enough of the talk and feelings have been built, it just becomes natural to feel less needful of T. Instead of feeling empty, I'm feeling a core building inside me.
I know its impossible to imagine this in advance. And it's important not to jump ahead and imagine being without T before all the bulk of this middle work provides a buffer. It takes much effort to have faith in this. And therapy takes as long as it takes, whether a few years or many years.
It's true that someone can be so constantly worried about being terminated that nothing happens to build a full relationship with T + self, and sometimes causes so much disruption that staying stuck in paranoia sabotages therapy. Some books say we need to grieve loss of our T, but some of us start that grieving before we even have a good experience with our therapist. We jump ahead. If a time to grieve over T does come, it shouldn't be the same raw grief that happened way back in infancy. There's a big difference between infant grief that's annihilation, and mature grief that's do-able and has a lot of good padding under it. But it isn't possible to know that when jumping way ahead of where you are in therapy.

So, it helps me to just focus on working with T and try not to think of how it will "end". I love the phrase someone has on the forum that goes like this: "If you're worried about the end of therapy, then it isn't time to end." Ending shouldn't be something the T does to you. Instead, it should be your own gradual idea to do some other things with some of the time or money, just because you feel less need of T. At least, this is the modern approach about the course of therapy. And another thing: By the time you've built strengths with T, you feel confident to speak up to her or him and negotiate what you need as an equal human being, and that right there takes the edge off fear of what T might do.