Choose someone you know very well, perhaps your husband or wife, and pretend you've just met. Arrange to rendezvous somewhere and casually meet each other for the first time. This suggestion can lead in a sexual direction, but it doesn't have to. The purpose is to see someone very familiar with fresh, playful eyes.
As your encounter progresses, see if you begin to feel the same way about this person as you normally do, or if you can actually sustain the feeling that you're meeting for the first time. How effective is he or she at revealing only a little of him or herself? How good are you at this?
Do you find yourself slipping back into familiar roles, or can you remain in character? Can you ask probing questions? See how far your partner will go in talking about his or her feelings. They could be about you, or about anything.
Allow yourselves to stay in these new roles, for, if you can, the entire evening. Sometime later, discuss with your partner what it felt like to have feigned unfamiliarity, to have staged a meeting, and to have gone on to get to know each other. Have you managed to rekindle feelings of surprise, of wonderment, of passion?
— Alan Epstein in How to Be Happier Day by Day