In the Hijou na Koibito series:

V.1 - Nessa no Hanayome (The Desert Sheikh's Captive Wife, Kazuko Fujita)
Tilda was shocked by her mother's words. Without her knowledge, her mother accumulated massive debts and was about to be evicted! But the man who holds the debts is the crown prince of Bakhar, Rashad, a former lover, and a man she'd hoped never to see again. He is a cruel man who sent Tilda away when she refused to be intimate with him. She's so shocked her blood runs cold when she hears his offer at their face-to-face meeting: "I will dissolve the debt if you become my lover once more."

V.2 - Ano Asa no Wakare kara (The Greek Tycoon's Defiant Bride, Natsu Momose)
Maribel has a crush on her cousin’s boyfriend, Leonidas, the Greek billionaire who constantly makes the tabloid headlines. She has a passionate one night stand with him, the day her cousin dies in a car crash! Maribel is convinced that she is nothing but a poor replacement for her cousin, yet she can’t help feeling hopelessly destroyed by Leonidas’s cold goodbye the morning after their tryst. Two years later, she is unexpectedly reunited with Leonidas, but she has a secret that she can never reveal to him. She had given birth to his child. Now, the truth has leaked to the paparazzi and tabloids alike!

V.3 - Yuuwaku no Chess Game (The Italian Billionaire's Pregnant Bride, Natsue Ogoshi)
“You won’t leave this game until every part of you belongs to me.” Sergio Torrente, an Italian businessman, is surprised at who he sees in the surveillance camera. The mysterious person making moves every night against his challenging chess display at the office turns out to be a cleaner clad in a shabby uniform. But how could such a beautiful woman be just a cleaner? Drawn to the mysterious woman, Sergio summons her and declares that she will play a game of chess with him every night, starting this very day!