How do I view my wife's calendar on my iphone?

My wife and I both have iPhones and now that Google is restricting the sync option for outlook, we are wondering if there is some way that we can also view each other’s calendar within our calendar. For example, with google mine showed up as blue, hers was pink. She knew what meeting I had and I could see when she was on call.

How do I set something like that up using iCal?