How can I avoid having to "OK"every entry from a shared calendar?

My wife and I share a few calendars. When she makes entries into 'her' calendar, I have to "ok" every entry in mine (as seen via the 'inbox' icon to right of the three red/yellow/green buttons). Why do I need to do that? (a) I am happy to see (and indeed wish to see) the entries without 'OK'ing, (b) this is not a feature in iOS (thankfully). It does not seem to be possible to switch off the need to OK. Any other ideas? Thank you