NQ-009 - Swapping partners right in front of each other before breaking up

I remember seeing this a long, long time ago. The fashion of the women in it really captures that Showa-era bubble economy vibe. It’s nostalgic. The plot is about 'couples on the verge of breaking up swapping partners to decide whether to split,' and since it's so old and features actresses I've never seen before (lol), it actually feels like watching real amateurs, which makes it quite enjoyable.