If both you and your wife are on Google+ I've found that direct sharing (i.e. you sharing only to her and vice-versa) seems to work reasonably well. It is browser-integrated and Google+ notifications generally mean you'll each find out something has been shared reasonably quickly.
I'm doing the same. I just share the link to the appropriate circle (I have a ton of overlapping circles - I'd rather select one circle from a long list than build up my share targets from small distinct circles) and voila.
They immediately get notified, and if they reply, I get a notification aswell, and neither of us had to leave the browser. With the G+Me chrome addon, this is all painless and straightforward.
