As Schopenhauer spent much time and energy on denouncing Georg Wilhelm Friedrich Hegel and Johann Gottlieb Fichte, opposing their views violently to those of Kant and himself, I would suggest reading one of their works.
For the subject is love, Fichte contemplates on it in his Anweisung zum seligen Leben (The Way Towards the Blessed Life), proposing to "shift love from the manifold to the one", that is, transforming it from being sensual, temporary, volatile to an enduring, eternal value.
Schopenhauer also regards sensual or romantic love as being too volatile. In his view, it is merely a masked sexual desire, hence a delusion having arisen only to secure the ongoing of mankind physically. He argues the only ethically acceptable form of love is the one that rises from sympathy as a means of self-knowledge, hereby contributing to the negation of the will.