I agree wholeheartedly that this whole dishonesty plotline feels contrived.
Like I can see why ml lied; i can understand him hearing "do you want to be the most important person in my life?" as a warning not to get clingy rather than a sincere inquiry.
But it never felt like mc had a very good reason to lie in the first place. Like ok he was feeling petty cause ml slutshamed him for no reason- this felt like a stretch. Then he continued the lie cause he wanted to keep it casual?? Like u can have a sex friend without pretending to be a cheater-Again very stupid logic from an otherwise sensible character. It feels contrived and out of character
If they wanted to draw out the drama i think mc needed better motivation to tell stupid lies.

i really don't understand how it's getting worse and worse. I feel like the author has no idea how dishonest ppl really act and they're just trying to force complications that don't match with the characters personalities. A story were dishonesty is well written for example is "payback", it takes mc like 80 chapters to realise that they're sad about the death of their family. In this story, i think the very emotional male lead just doesn't match with the dishonest characteristics, because ml is always sulking, emotinal, clingy and obviously tries to appeal to the main character. But now suddenly when the mc asks whether they want to be the most important person in mc's life, they lie and act distant??? Makes little sense even with the sudden sob story of a backstory. It feels forced and frustrating.