Kon'ya no Otsumami ~Musuko-tachi no Yome wa Mitsu no Aji~

The main character has been living alone and has felt lonely ever since his wife passed away due to illness. One day, though, his luck completely changes. His three sons have come back to live with him, each with his own wife. This is the start of a life full of temptation with his three gorgeous daughters-in-law! [Translated from DLsite]