Tunnel Rat - Chapter 1: Milo

Anna Jones, an Australian travelled with her fiancé Lu Jinhu to marry in his home country, only to find out that she has been duped by him and robbed of everything that she owns. A quirk of fate allows her to marry CEO Hou Yi, who was meant to on the same day marry his finance Yang Lin, who in fact married Lu Jinhu. Marriage for Anna, started as a plan to gain some measure of revenge on Lu Jinhu, and for Hou Yi to prevent Lu Jinhu from obtaining the family company however fate had something different in store for them. Not only did they achieve their initially goals, but their relationship turned into something else, that could last a lifetime despite the cultural differences and the trouble Lu Jinhu and Yang Lin caused them.

Ace Carter Greyson, her husband of five long years forcefully divorced her on the night of their fifth wedding anniversary. Reason? Simply because she can't bear him a male heir.

Phoenix begged him to stay but his decision was firm and unbendable so she finally let him go. Her life was even more shattered after she discovered his long time affair with his secretary, and now, the mistress was pregnant. Just months after their divorce he married the impregnated secretary.

Phoenix's world suddenly turns upside down when she discovers she's four months pregnant.

Based on the popular Vocaloid series, by HoneyWorks, called “Kokuhoku Yokou Renshuu (Confession Rehearsal)“:

Natsuki, a third-year at Sakuragaoka High School, who holds unrequited feelings for her childhood friend, Yuu, who’s in the Film Club. However, instead of being honest about her feelings, she makes him be her confession “rehearsal” partner. Unable to say her true feelings, things start to get complicated when Miou and Akari, who are also in the Art Club, get involved! Will she ever be able to confess for real!?

Time travelling from the majestic era after the Recuperation of Reiki, he became Kimura Kazuki, a 16-year-old high school student in Japan, one year before the Reiki Recuperation.

Tentatively, he set out to hone himself to the bone, burning candles at both ends to stockpile resources in preparation for the imminent Recuperation of Reiki. His goal was to be many steps ahead of all humanity when the time comes.

However, it seemed like fate had decided to play a cruel trick on him.

One year later, the Recuperation of Reiki… did not happen as expected.

- Description from Novelupdates