Risks and burdens
If you love someone, you open yourself up to suffering. That is the sad truth. Maybe they will break your heart; maybe you will break their heart and never be able to look to yourself in the same way. Those are the risks. You see two people and you think “They belong together”, but nothing happens. The thought of loosing so much control over a personal happiness is unbearable. That is the burden. Like wings, they have weight. We feel that weight in our backs. And burdens do not allow us to fly.