I read that manhwa quite long ago, I don't remember it quite vividly, so I don't remember the scenes you talking about. But I agree with you about his behaviour then.
A toxic trope that is called “romance.” When will people finally understand that sex without active consent…
well, in the novel they didn't had sex, the make lead was just pretending that they had sex. it was all an act. Just stating the fact, I didn't like the manhwa or drama either. The female lead was too annoying for me to watch in the later part, so I dropped it.