Absolutely.
- Log on to your google calendar from a PC. (or use the standard interface instead of mobile from your phone if you must)
- Go to Settings / Calendar Settings
- Click on the Calendar tab
- Under Calendars you'll see your email address, and to the right of that a column for Sharing.
- Edit the settings for Sharing
- Under Share With Specific People, enter your wife's email address, and select what rights you want her to have. I have my wife set to "Make changes to events", that way she can add events to the calendar.
- Click Save
- On your wife's phone, configure her calendar to view yours instead of hers. You can have it set for her to view both, but for me it's far easier to just share the one calendar; less possibility of her adding events to hers instead of mine and then wondering why I don't see it...