PREGNANT BY THE MILLIONAIRE

Hebe secretly admires, Nick, her boss at the art gallery where she works in London. She spends a passionate night with him, but her happiness ends the next morning. Nick throws her away, saying, "I would never have expected you were a mistress of Andrew Southern!" Nick shows the stunned Hebe a painting by a legendary artist, Andrew Southern—a portrait of a woman with watery eyes and a smile lying on a bed. The woman is a spitting image of Hebe! Nick does not try to hide his disgust at seeing her in the painting and accuses her of being after his money. But Hebe has never met the painter and she is truly in love with Nick, even though he doesn't believe it...

In the Miwaku no Dokushin Kizoku (Bachelor Cousins) series:

V.1 - Kojou ni Tsudou Ai (To Marry McKenzie)
Eligible, elusive...and engaged!

Logan McKenzie liked his life exactly how it was -- with no surprises, and without a wife.

Then Logan learned his mother was about to marry for the third time, and that Darcy, his very pretty stepsister-to-be, was in danger of being hurt by that marriage. So he found himself getting involved -- not only in trying to prevent the forthcoming nuptials, but with Darcy herself...and his carefully controlled existence was turned upside down!
- from FictionDB

V.2 - Nazomeita Bijo (To Marry McCloud)
Fergus McCloud couldn't quite remember how he'd first met Chloe Fox...but circumstances indicated that they'd slept together pretty soon afterward! Actually, they hadn't. But Chloe's mission was to persuade Fergus not to publish a book that would ruin her family. What better way than to prolong the pretense of their being lovers? Only, Fergus wanted to rediscover the delights of their night "together"—and he intended to be present this time...in mind as well as body!

V.3 - Ubawareta Kuchibiru (To Marry McAllister)
Brice McAllister, the world's renowned artist, instantly falls for Sabina as soon as he meets the gorgeous supermodel's gaze. He has agreed to paint her portrait only to quiet the insistent billionaire who demanded Brice to paint his fiancee's portrait at any price. The meeting arouses his desire to draw Sabina. However, once he starts to work on the portrait, Sabina does not hide her fear and avoids his gaze. It is as if she believes allowing him to draw her is a sin...

English publication via Renta!, part 2

When Leonie is invited to Rachel Richmond's English country mansion, she's immediately impressed by the famous actress's sophisticated style and impeccable manners. Her first impression of Rachel's handsome son Luke, however, is a different matter entirely! A proud, aloof man, Luke Richmond takes an instant dislike to Leonie, and, used to getting his own way, he repeatedly asks her to leave. But Leonie has been commissioned to write Luke's mother's biography; she's not going anywhere especially now she's realised that Luke's got something to hide!