SPRD-573 - My mother-in-law is way better than my wife... Yukiye Nono

This is an early entry in the series. The mother has a fling with a delivery guy, but the physical relationship with her son-in-law feels forced and lacks narrative logic (why would she give in so easily?), making the drama feel half-baked. However, actress Yukie Nono is very expressive and really gets into it, so it's worth watching for that. She's on the chubby side, so I recommend it if that's your type.