Relationships are what everyone wants in their lives in which some want to be valued, invested, and loved. Seems fine for now but there is one element in your life that needs to be prioritized before, during, and after a relationship; YOURSELF. Sometimes a relationship could go sideways when a partner lacks a 'relationship principle ' where it could be emotional attachment or lacking in the three C's in which it would then result in a 'Casual Relationship'. So when a break-up happens or rejection (if a person were to confess their love for someone), there comes a feeling of sadness, depression, and demoralization in finding love again as it can somewhat connect with a phrase such as "He/She was my source of my happiness". In this episode, Fady talks about how your relationship shouldn't primarily revolve around your partner the whole entire time, plus goes through the distinction between a 'casual' relationship and a 'serious' relationship. 

P.S. I'm not a dating expert nor do I have multiple experiences in relationships, I just happen to understand one or two things about maintaining and cultivating a 'healthy relationship'.