calendar shared with family members is missing
My calendar suddenly stopped appearing on my iPhone. I've had the calendar for more than 10 years. It was originally set up when only my husband had an iPhone. He "shares" the calendar with me. But as of this morning, it is missing. What would have caused the calendar to disappear from my iPhone. I can see my calendar on my husband's phone and it says that it is shared with me.
iPhone 6, iOS 12