I don't think there is this problem. Lucy is the sweetest girl in the world and will perfectly understand what's going on. I too was shocked by the way she appeared at the end of the prologue, alone, in the dark, while everyone is happily doing something with someone else. As if everyone had had the opportunity to move forward in their life, with new enthusiasm, new paths to take, while she did not. She, who thought she had found what she was looking for all her life when our protagonist appeared in the city, in the end she seems to be the one who not only did not make progress, but who even made one back, returning to be alone and sad . It broke my heart.
But it is very likely that all this will simply lead to a new confrontation, perhaps hard, with Lucy who (as has already happened other times when her need for affection-attentions-to be loved has come out) will take the protagonist head on and will take his time. In the sweetest way possible, making our little heart melt.