You can use Family Sharing to sync your Calendars:
https://www.apple.com/icloud/family-sharing/
With Family Sharing, you can continue to share all of your iTunes purchases OR
You can keep the current Apple ID as your iTunes ID that both of you use and which you both have signed into the iTunes & App Store on your devices, and then each of you can set up your own Apple ID for iCloud, Messages, FaceTime, Mail, etc.:
Use one Apple ID for iCloud and a different Apple ID for Store purchases
You can use different Apple IDs for iCloud and Store purchases and still get all of the benefits of iCloud.
iPhone, iPad, or iPod touch
- When you first set up your device with iOS 5 or later, enter the Apple ID you want to use with iCloud. If you skipped the setup assistant, sign in to Settings > iCloud and enter the Apple ID you’d like to use with iCloud.
- In Settings > iTunes and App Stores, sign in with the Apple ID you want to use for Store purchases. You might need to sign out first to change the Apple ID.
Mac or PC
- Enter the Apple ID that you want to use with iCloud on your computer:
- Mac: Enter your Apple ID in Apple () menu > System Preferences > iCloud.
- Windows 8: Enter your Apple ID in the iCloud Control Panel. To access the iCloud Control Panel:
- Move the pointer to the upper-right corner of the screen to show the Charms bar.
- Click the Search charm.
- Then click the iCloud Control Panel on the left.
- Windows 7 and Vista: Enter the same Apple ID in Control Panel > Network and Internet > iCloud.
- Enter the Apple ID you want to use for Store purchases in iTunes:
- iTunes 10: Store > Sign In.
- iTunes 11 or later: iTunes Store > Quick Links: Account.
If you're using Windows 7 or 8 and can't see the menus, learn how to turn on iTunes menus.
Once a device or computer is associated with your Apple ID for your iTunes Store account, you cannot associate that device or computer with another Apple ID for 90 days.
Learn more
Learn more about Apple ID.
If you use a different Apple ID for iTunes and iCloud, and want to restore from a backup, first enter your Apple ID for iCloud. After your device restarts, you'll be asked to enter the Apple ID that you use with the iTunes Store, App Store, or iBooks Store. Learn more about backups in iCloud and iTunes.
Post back with any questions
Cheers,
GB