What He Who Doesn't Believe in Fate Says Vol. 5 (manga)

Once Yuka could see the red string of fate, her romance with her long-time friend Kosuke bloomed! Things were slow at first, but now that they’ve had their first kiss. there’s a steady and comfortable rhythm to their time together. But a beautiful woman has arrived to throw them out of sync.

This stranger claims to be Kosuke’s one true love, and the red string disappears from Yuka’s sight! She’s always believed in fate, but what will she do now that it’s abandoned her?