How do I share calendars on S7?

[AC Question]

On our prev S5, the calendars on my phone, and my fiance's, automatically updated...so we shared calendars. This was the app that's automatically included on the phone...nothing we installed.

Now we're on the S7, still using the included calendar app, and nothing I enter (and I enter the vast majority of appointments, etc.) is showing on his phone. No reminders, nothing...

Any way to fix this? Thanks in advance!!!