Worldwide Beasttaming: I Can Design Evolution Lines - Chapter 294 - : Investigating Memory, Change in Emperor Liquid!

For the large sum of money to help her husband, she chose to be a surrogate mother covertly. Her sweetheart was out of trouble, but she became the woman of loose morals in his eyes. Misunderstanding, disappointment and sadness forced her to divorce the man she loved from the childhood.

When she was determined to start new life, another man burst into her life. “You are my baby’s mommy and you are my wife!” A big surprise hit her that her baby’s Daddy, the man she surrogated for, fell in love with her at his first sight.

His deep love convinced her to believe the affection of love again. Unexpectedly, her ex-husband returned to beg her recombination. One was her childhood sweetheart, and the other was the man who loved her and gave her hope for a new life……Facing the two men, what is her choice?
 

- Description from Novelupdates

In the eyes of outsiders, Hyuga Yuuto is a genius in the traditional sense of the Hyuga family:

Tough, strong, gentle, and calm, he is a partner worth relying on at all times.

However, no one knows, in countless silent nights.

The young genius of the separation family stroked the caged bird engraved on his head and fell asleep with the sharp needle in his mouth, fearing that in his sleep he would reveal the madness and anger deep in his heart——

“What Uchiha Itachi can do, I, Hinata Yuuto, can’t dare to do?”

- Description from novelbuddy

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.