I think that its normal to be sad that another part of you is going. She holds some of your true self and you want a piece of her experience, at the same time you want her to care about your experience. Getting closer to her makes you more free. In fusing alters, nobody is lost, or dies. Try to imagine a braid, one strand covering the next and so on, this is what it is like when you blend together.
Nobody dominates, nobody disappears.
I think consent from the alters is crucial, Kellie may need to take a time out from consciousness, but that does not mean she won't come back. We used to struggle for control a lot before we learned that we could all be out at the same time, if we shared. Try to find out what Kellie's job is, and maybe you will learn why she no longer feels needed. I'm DID and my life is going to pieces. I can't seem to handle anything anymore.