Currently Being ModeratedJun 4, 2013 9:40 PM (in response to swandy)
First of all you need to be using the same AppleID on her iPhone and the Mac with Aperture in order to see the same "My Photo Stream". (I'm assuming you are or you wouldn't see any of the photos. But just in case...)
There is more than one Photo Stream. Your main Photo Stream is called "My Photo Stream". This is only visible to Macs and iOS devices signed into the same AppleID. You can have other "Shared Photo Streams" that you can share with other AppleIDs or even publicly using a URL.
To share a photo to Photo Stream, you select it in the browser and choose (right-click) Share->Photo Stream and a dialog will appear. Within this dialog there's a popup menu that determines where to share it. You can select "New Photo Stream" which will create a new Shared Photo Stream. Or if you've already created some Shared Photo Streams, they will appear in the menu and you can add to them.
There's an additional entry in that menu called "My Photo Stream". This doesn't appear if the photo you are sharing is already in the My Photo Stream location in Aperture. So you cannot add a photo in My Photo Stream to My Photo Stream if that is where it is already located in Aperture. If you select a photo from inside a project in Aperture you will then see the "My Photo Stream" entry in the Share->Photo Stream dialog.
Solutions for you:
To get a photo back into My Photo Stream for other devices to see, go to the project where the photo lives and Share->Photo Stream and select "My Photo Stream". By default, Aperture imports all Photo Stream photos into a monthly project automatically. If you disabled this in preferences, you could manually import it using drag and drop from My Photo Stream to a project in the library sidebar.
To get a photo into a Shared Photo Stream, select it and choose Share->Photo Stream and select New Photo Stream from the popup menu. Give it a name and description. If your wife is using the same AppleID, it will automatically show up on her iPhone in the Photos->Photo Stream app. If she is using her own AppleID, you can share it with her by adding her AppleID in the share dialog.