im rewatching and what I think kicked it off was Luca’s snide comments. I think Dami probably does feel a little guilty, but he has a point: they are all single. Nobody has agreed to be exclusive.
Luca was initially egging Dami (and the other guys) on, then made the comment “he moves faster than an F1 car”, which made Dami turn around when he was up with Summer on the balcony. So presumably he heard Luca.
then later when Dami mentioned he’d kissed summer, Luca was basically telling him to do more in bed. Dami said he didn’t want to because he still liked Indiyah and preferred Indiyah, but Luca was basically like, you might as well crack on with Summer in bed now you’ve kissed her. I can see why that would piss Dami off, regardless of any feelings of guilt or not. He’s trying to sabotage couples but acting like it’s just laddy banter and it’s very transparent.