perhaps the canonical regulus fell in love before he leapt to his death. not with the flamboyant and energetic james potter, or the sheer force of nature that is barty crouch jr., nor even with a highborn slytherin lady. maybe regulus simply learned about love from a figure who goes unnoticed in history, one never worth mentioning, but whom regulus secretly cared nonetheless.
an unknown person, half-blood or muggle-born, who knew how to open regulus’ critical mind and carved a place in his heart as if he were born to do so —even if no one knows who he is, his name, his face. peradventure, regulus sacrificed himself because he wanted a better wizarding society for they, or because he didn't want to live with the consequences of his actions. whatever the reason, maybe there is someone out there in history who knows the taste of regulus’ love.
or, in reality, the canonical regulus died without love. but no matter which version it is, regulus black is a truly tragic story.