I have the same situation and it works flawlessly for me. I have my wife share her calendar with my gmail account, so the calendar displays with my account-- i.e., I did not set up her calendar separately.
we have the same situation - we share our calenders for each other
but when doing so, her calender appears in my em-clients ‘calendar tree’ (and vice versa)
together with all other shared calendars (holidays,…)
my entries are the red ones and her entries are the blue ones
my entries will be automatically refreshed each time em-client syncs - but her
entries often will be refreshed only when i shortly deselect an re-select her calendar