Place it at the end of a rejection scene, after the confession lands, then follow it with Emotional Damage for a second reaction. For a different finish, put Scream Meme after it instead, keeping the heartbreak moment as the centre of the edit.
About this sound
A man speaks the heartbroken line in a shaky, stagey voice, then collapses into a long, climbing scream of anguish that lasts about eight seconds. The jump from earnest confession to wildly overdone wailing feels funny and melodramatic rather than truly sad, making a minor romantic setback sound like a complete tragedy played for laughs.