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This happens because you use the same iCloud ID on both devices. Sign out of iCloud on one device, and sign in with a different ID. This should stop sharing your calls and texts.
It's possible to share iCloud calendars. You can do this on your iPhone.
Open the Calendar app, and tap Calendars at the bottom. This will show you all your calendars set up on the iPhone. Tap one of the calendars you're already using, or add a new calendar. After creating the calendar, tap it once more. Now you choose the colour, and you can share the calendar with someone. Enter the email address. Your wife (in your case) will receive an email, where she can join your shared calendar.
Hope that helps.