Hi Kelly,
I don't really have any advice, well maybe I do, but even more importantly, I just wanted to send you a huge, warm, sloppy, teary, hug.
I am so sorry this is happening to you, but I don't think you need to necessarily see it as an ending but rather a beginning.
I'm not sure your partner is, or has been lying. I'm thinking his emotions are likely not even solidified in his own mind.
If he is feeling like he's in a caretaker role, than chances are he may be feeling a little burned out, like most caregivers do from time to time.
I think you are wise to not quickly move out, but I would suggest that you possibly evaluate and analyze the situation to see if there are places where you might be able to take the pressure off of him.
If you want to work this out with him, I would not harp on the lying and trust issue stuff because this is not going to strengthen your position.
If he feels that he has become your caretaker, than it's time for you to do as much as you can for yourself. Gain as much independence as you can back. Show him that you are in this relationship because you love him rather than need him.
Once the pressure is off him, he may begin to see you back in the light that drew him to you in the beginning. Either way, you have got to begin learning how to care for yourself because, in the event he is serious, you've got to be ready to move on to the next phase of your life.
Seriously, I don't see this as terminal, but more so a wake-up call that he's needing some relief from the pressure cooker he apparently feels he's in.
I so hope this turns around for you...
And, don't cancel that appointment. You need this, whether you eventually go or stay.