The Billionaire's Surrogate Wife

Samuel Walters is a Billionaire. In all his life, he never thought his life would be this complicated.
All stories start when his lover, Valerie Anastasia, who works as a famous model, refuses to return to Los Angeles because he collides with the schedule of fashion shows around the European continent.
Samuel, who had promised to bring his future wife to a mother's birthday party, is undoubtedly confusing. He struggled to find a good reason but couldn't also visit available.
Until unexpectedly, that crazy idea appears.
At the assistant's suggestion, Samuel asks Ariana Grey, the girl who works as his secretary, to be a temporary partner so the mother does not disappoint.
Unfortunately, the whole Walters family likes Ariana. They even urged Samuel to hurry and maybe marry the beautiful girl. That's all; Ariana's cleverness attracts people's attention and makes some of Samuel's business relations willing to establish cooperation. Not a few offer themselves to sponsor their wedding.
So, will Samuel still marry Ariana while he already has Valerie as his lover?