Unclear desire is like an unfixed compass.
You've heard that art imitates life. Remember Jack Sparrow's compass from the "Pirates of the Caribbean" movies? That is art imitating life in an esoteric way.
If you don't have a clear idea of what you want or need, then it is hard to go find it.
The same is true, to some extent of the 'moral compass'. If you don't have some idea of what is right or wrong for you, or to cause no harm, then the compass spins and we feel lost, even unloved.
The Lovers are a major arcana card for a reason. Desire contributes to what we attract into our lives. If we desire true love, like attracts like. If we focus on superficial things, we surround ourselves with a shell. If we navigate by compassion, we find compassionate seas.
Deciding what you desire is the first step in first step toward finding it.