The pattern you described of obsessing over someone until they reciprocate your feelings and then losing interest once they do can be a complex and multifaceted emotional experience. While I can't offer a definitive answer tailored to your specific situation, there are some potential psychological factors that may contribute to this pattern:
Chasing the Unattainable: Some individuals may find themselves drawn to pursuing relationships with people who seem unattainable or challenging to be with. The excitement and desire for the unattainable person can create intense feelings, but once they become available, the allure of the chase diminishes, and interest wanes.
Fear of Intimacy: People who struggle with a fear of intimacy may become intensely infatuated with someone from a distance but find it difficult to maintain that connection once it becomes more emotionally intimate. This fear might cause them to push away or lose interest once the relationship becomes more serious.
Lack of Self-Worth: Sometimes, people may seek validation and self-worth through the pursuit of someone else. Once they receive affirmation or love from the other person, they may not feel the need to continue seeking validation, leading to a decrease in interest.
Idealization and Disappointment: During the infatuation phase, it's common to idealize the person you're interested in. However, when they become more real and flaws are revealed, it can lead to disappointment, causing the feelings to fade.
Avoidance of Vulnerability: Being loved back means opening yourself up to vulnerability and the potential for emotional hurt. Some individuals might withdraw to avoid this vulnerability, leading to a decrease in interest.
Lack of Genuine Connection: The initial intense feelings might be based on projection or fantasy rather than a genuine connection with the person. Once the reality sets in, it becomes clear that the feelings were not built on a strong foundation.
Attachment Styles: Attachment styles developed in childhood can influence adult relationships. Someone with an anxious attachment style might obsess over unavailable partners but withdraw once the relationship becomes secure.
If this pattern is causing distress or negatively impacting your life, it might be helpful to explore these feelings with a therapist. A professional can help you gain insight into your emotions, patterns, and underlying beliefs, and support you in forming healthier and more fulfilling relationships. Remember that self-awareness and understanding are crucial steps towards building meaningful connections with others.