My Forbidden Romance

The protagonist lives a life with her husband in which they only go through the motions of being husband and wife.
Her daily life is bland and unhappy.
One day, the protagonist has a one night stand with a man she meets at a nearby bar.
She knows that she has betrayed her husband but does not feel as much regret as she should.
The protagonist begins to work at a publishing company in order to start fresh.
However, the president of said publishing company begins to make advances on the protagonist and she falls into a relationship with him.
On top of all this, a handsome gym instructor comes into the picture as well...
Thus, the curtain rises on a new and exciting adventure.