I don't think it will happen. First, you can fake feeling good with someone during sex but you can't fake feeling bad. The body, especially if you're with someone who knows all your sweet spots like Jiwon does, is going to respond unless you're just too out of it mentally. And even then, sometimes the body takes over because friction.
Second, that's a step back for DG as a character even if it would be satisfying. And I'm talking about the literal act of pretending to be bored in bed here. One thing to say no, or to get up after leaving and say "never again". But DG has already spent so much time lying about his true feelings for the sake of Jiwon. Lying just to hurt his pride so he doubts his skills in bed doesn't really progress his character or fall in line with the person who admitted his fault in their parting, even if it strokes his vindictive side.
This is also why Jiwon probably asked him to sleep together again. Whether he's talking about one last time or as his sex partner again we don't know yet, but the implication is that Jiwon has decided on some level to be honest about what he wants. They've moved on from the people who hurt each other and had expectations they couldn't deliver on. They haven't moved on from the people they've become since their parting. If anything I think DG would avoid him altogether or give in one last time and then get up and leave.
Okay so on the latest chapter alex asks to have sex with him and he’ll forgive him and I understand why people want DG to refuse 100% but like, I kinda want DG to accept and to kinda just have a bland expression when doing it and to ignore him in a way that alex did to DG, having the roles reverse of him not giving a shit makes my dick so hard wtf