I completely agree with this statement.
Healthy individual behaviour strengthens the quality of any relationship. The best kind of romantic relationships are an extension of an already established strong foundation from each individual’s life.
When you keep focusing on building your mental/physical health, you become more aware of the type of person you want to be, and the type of person who fits your lifestyle.
Also, two people who are already happy with their single lives, tend to depend less on each other for fulfillment. This releases a huge pressure for both parties