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.
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.