Shared outlook.com calendars on Android

[Windows Central Question]

Hi,
I recently moved from Windows Phone to mobile. My husband and I both have outlook.com accounts and use these for our calendars. When we both had Windows Phones, everything worked fine - we could share our calendars with each other. Now on Android, I can sync my own calendar to my phone - but my husband's calendar doesn't appear. Any ideas on how to solve this? It surely can't be that hard...