The sun is Made of Flame, Reach for it and Fear it's Heart or Melt in it's Gaze

Izuku was many things-strong, emotionally inteligent, friendly, sensitive, weak- but if there was one thing he very much was it was happy in his soulmate relationship with Kacchan-Katsuki Bakugo-... right? So you can imagine the hurt and heartbreak he felt when he learned Kacchan had fallen for their classmate Kirishima, had taken a liking to the third's soulmate, and planned on cutting his and Izuku's soulstring to tie it to Kirishima. Unsurprisingly Izuku was at a loss as to what to do. (TW, topics of sh, abuse, and thoughts of suicide. Stay safe, stay alive.)