what does the cut with the thread symbolize again? ive forgotten

I think it resembles how everytime that Heejae hurts Garam (because he is a knife), Garam heals himself and shuts out his anxieties. But as his anxieties and realizations about the relationship furthered the thread got close to snapping. Ig it's like how when people talk about patience they say "that was the last straw" lol

I think it's symbolizes garam's acceptance of heejae's attitude/issues. Everytime heejae hurts/disappoints/distrusts garam, we see that "wound" opens. Versus when garam falls more in love/feels happy with heejae, the wound stitches up.