In romantic relationship, people often say they are looking for other half of themself to make it complete. It is very much true. If there were identical twin of yourself except sex chromosome, she or he might have been your perfect other half. You might be totally infactuated by such individual. Studies after studies have found lovers often look alike. Beauty is in the eyes of beholder. We often find most attractive movie stars sharing similar physical features to ourself. So there will never be consensus about who is the most beautiful person on the earth.
On the other hand, inbreding is also harmful to our gene. So people who grew up together almost never got married even though they might not biological related.
At end, the perfect mate would be some one who look like youself but never together before.