In the Kincaid-ka no Yuigon Game Series (The Payback Affairs series):

V.1 - Boss to Hisho no Juunikagetsu (Shattered by the CEO)
All's Fair In Love...And Business

CEO Rand Kincaid had never been coerced--until his entire future was at stake. Under the stipulations of his father's will, Rand had to rehire Tara Anthony as his assistant. It was either get along with the one woman who'd dared to leave him first, or lose his family empire.

But before Tara would accept, she gave Rand her own demands. She wanted a second chance, with Rand back in her home and bed as her lover. And nothing prepared him for where this arrangement would lead.

V.2 - Itsushika Hanayome Kouho (Bound by the Kincaid Baby)
The affluent Mitch Kincaid's livelihood hangs in the balance because of his father's peculiar will. Unless he takes in his father's illegitimate child and looks after him for one year, Mitch will lose his entire fortune. The child is now under the care of its aunt, Carly. "I'll give you a hundred grand for the child. No-five hundred." Mitch offers Carly riches, but she refuses. She claims she doesn't need any money, and that she'll only cooperate on the condition that she, too, lives at the Kincaid manor. Dammit, what is she after? Does she intend to slink into his bed - and push him into marrying her?

V.3 - Nefuda Tsuki no Ai (Wed by Deception)
Ever since her husband died eleven years ago, Nadia has been busy playing and working to take her mind off things. Now, according to her father's strange will, Nadia is to shut herself in a Dallas penthouse. Her curfew is at midnight and she is not allowed to see any of her friends or go to work. If she disobeys these conditions, she will lose all of her inheritance. What is my father trying to do by keeping me locked in? Two months after this lonely and depressing life started, her penthouse neighbor, who has been away, suddenly appears in front of her. But the minute she sees him, Nadia faints out of shock!

English version via Renta!: Vol 1, Vol 2, Vol 3