I have found that having a destination helps. My wife will say that she is going shopping, have her hair done, visit friends or whatever and I leave early and meet her there. She brings a change of clothes and a towel. I do a quick dry-off and change. After that, the day is hers. I have had a great 30-60 mile ride and she gets to do what she wants to do. We do that two or three times a month. The rest of the time I just ride my regular routes, but throw in some sprints or hills or any other variations that come to mind. Works for me.