If I'm remembering the Gilded 5 of Cups correctly, I always got the sense that this warrior is weary - nearly defeated by the three cups that have spilled (i.e. the situation that has broken his heart.) He's down on bended knees, tired, spent and unable to see the two cups that remain upright at the moment.
In this way, it makes me think of someone who has suffered a loss, who, at the moment, can focus only on that loss. It has nearly crippled him...but he is not totally laid out yet. If he can only look up and see those two full cups, he will understand that he hasn't lost it all.
But he is being pessimistic right now, and if he continues to focus only on the loss, he runs the risk of being devoured by self-pity. Still, he is the only one who can look up. No one else can do it for him. And once he does...once he is able to move on to the six of cups, he will be able to look back at what he went through to find his current happiness, all the stronger for having suffered that loss of the five in the first place.