When my wife rides, she is not interested in a hammerfest (to her). She is interested in doing something with me and in having a clear set of landmarks and destinations. I also have to plan things out so the scenery varies. Try this:

- Plan out a loop ride that you'll do together. Ideally, the route would allow you to ride side by side and have a conversation (MUP, low traffic road, etc.).
- Ensure that there is something interesting every few miles along the loop. Plan on stopping if she wants.
- Bring a picnic lunch (you carry everything). Stop somewhere nice and relax together.
- Let her set the pace the entire time. Spin at a high cadence or ride a mountain bike if you want a bit of a workout. I've seen some guys get a trailer and tow all the gear, water, and maybe some rocks around.