Bachigai na Kyuukon

Jake and Rachel were enemies over the custody of baby Emma. However, the court decided for them to "raise Emma together," and from that day on, they stayed at each other's houses to take care of Emma. As time goes on, Rachel realizes that Jake hides a sensitive heart behind his seemingly arrogant demeanor. And on the night she hears about his sad past, the two of them share a passionate and deep kiss, but...?

(Source: Harlequin, translated)