This is a fun variant on the time loop trope, because in this case there are several people who are aware of the time loop but the two leads are not included in that group, so they're just very confused by what's happening around them.
(In this case, it's the male lead's family who remember their previous lives, but not the male lead himself, or the female lead. So far at least. So this also becomes a variant on the trope of the extremely friendly in-laws.)
Also generally, it's quite fascinating how many romance manhwa seem just fundamentally more interested in parent/child, sibling, etc. relationships than romantic ones.