Responses
I agree, when I was reading this, i thought "that's why, i can't blame her" he was a solace in her life at that time. We cannot blame Na Haesoo because it's not easy to get out of a toxic rs and forget about a decade of love they once had, especially when it's the only one you have experienced (no other rs).

These are my rambles and thoughts (kind of long read FYI)
While I do acknowledge and admit that I absolutely despise Mincheol. Along with flashbacks being tedious. I don't think the author's point was to make us (readers) like Mincheol.
Felt more like a why. Explaining why Haesoo was still with this man. Why she still loved him even at his absolute worst (prior to cheating - more on the debt).
It even makes sense why she's sensitive to finances. How she grew up, and what Mincheol did. Doing odd jobs to give something to someone they love.
If we ignore the ML (for a moment) Haesoo's life is so unimaginably tragic but so real for relationships. To stay stuck in a toxic relationship blinded by the past. The person they fell in love with and the person they were still waiting for. I love how the author did this. It shows that not everyone stays the same in relationships.
When I finished reading this chapter, all I could think and say was, "That's why she loved him. I can't even fault her for loving him."
Now I don't want her to get back together with Mincheol. Hate the guy. But these are just my thoughts and rambles on the chapter and story in a sense #-.-)