I am in a long distance relationship with someone suffering from SZ and I have had to learn more or less the same lessons.
Intellectually it is entirely possible to figure out why she would often withdraw and isolate herself and even be completely unreachable. But emotionally living with that is a lot harder and getting to that point is a tough learning process. I am still working on it.

It is so important to understand that, which in other kinds of relationships could easily be seen as rejection, in situations like this is something entirely different. The difficult part is to overcome the conditioning of a lifetime and to get used to many of the stranger phenomena and patterns of behaviour associated with SZ.

It is very important to try and reduce stress factors as much as possible. That can be tantamount to walking on eggshells. Its a matter of learning what the major stress factors and triggers are and to try and avoid them or even preventively mitigate them.