In relationships, we tend to naturally gravitate towards people with traits we like. Some people are aware of what their type is, based on what they typically go for and others, although unaware, can kind of see a specific trend in their exes if they take time to investigate.
The interesting thing that often happens is, we attract people who are similar to ourselves. If for example you are a sapiosexual, which is someone who is sexually attracted to intellectuals, you will find yourself attracting other sapiosexuals.