Psoriasis is not a contagious disease. Psoriasis is an immunological disorder but has varying severities. Everyone need not neccessarily get the severe form of disease. It has various exacerbation factors like stress, certain drugs, infections. Psoriasis can be kept under control by taking regular medication and once you go in remission you may stay in remssion for a good amount of time. It may exacebate in winters and the future exacerbations may be mild and medications required whether topical or oral will depend on the severity and extent. It is not that continously for lifelong you require to be on medicines. During remission you may not need anything. It would be nice if apart from taking treatment for psoriasis you also do yoga and mediation as it would help in improving your stress response. Its better both you and your wife consult a dermatologist. Please remember psoriasis is not contagious. Its not that psoriasis has spread from you to your wife.