not a partner, but i have forgiven someone who hurt me a lot for many years. it took a period of no-contact, them figuring out on their own both what they did wrong and how to stop repeating those actions, sincere repeated apologies, a lot of physical distance, and a repeated pattern of good/respectful/boundaried/calm interaction with them before we could reconnect and i could truly say that i primarily associate them with positive emotions. but it did eventually happen.
personally, my motto is that every couple should break up at least once, for minimum of 6 months. it gives you a chance to see your partner for who they REALLY are, without rose colored glasses, and then figure out if you're still into them. it also shows you who they are after a breakup -- do they trash talk you to all your mutual friends? stalk you? or do they handle rejection w/ maturity? i've done that three times -- for two of them, the second time we dated was better than the first but ultimately unsuccessful, and for the third one, i think this might be my person for life. so it never makes me sad when the main couple in a manga/manhwa break up for a bit, i find it relatable instead of sad.

If yall was in Euihyun position, would you forgive taeju?
Like I know Euihyun is his own fictional person, but since we are a real human being … would yall forgive taeju after everything?