Kozure Batsuichi, Saigo no Koi wa Numa deshita.

A scummy but perfect bachelor soothes the heart of a hardworking single mom!! Touko is a single mom who spends her days working and raising her kid without relying on anyone. One day, Touko collapses from overwork and is rescued by a male university student who lives in the unit next door. He's a handsome-grade eligible bachelor, but also a bit scummy. For Touko, who hates men, it seems to be the start of a final love... (Source: Kadokawa, translated)