Mrs vs Mistress

Cassandra’s Vow

Cassandra Kane smiled until her cheeks hurt.

The gala carried on as if nothing had happened, crystal glasses clinking, violins playing, and people laughing about money and business. But Cassandra could feel it. Eyes. Watching her. Waiting for the wife to break.

She didn’t.

Her gown sparkled when she moved. Her posture was straight, her laugh was soft, her face calm. To the world, Cassandra Kane was perfect. The perfect wife for Alexander .

But inside, she was burning.

That woman. Aria Monroe. She had walked into the ballroom like she owned it. She kissed Alexander like he was still hers, and smiled like the whole room belonged to her.

Cassandra’s hand tightened on her champagne glass until her knuckles went pale.

Not in front of me. Not in my marriage.

She excused herself from the women she had been chatting with and walked onto the terrace. The night air was cool on her skin, but it couldn’t cool her anger. She caught her reflection in the glass door—flawless, untouchable, like the perfect wife she was trained to be.

Her father’s voice echoed in her head. Control, Cassandra. Always control. That is how you win.

For a moment, her mask slipped. Her chest rose and fell too quickly. Her eyes flashed with pain. This wasn’t just about a kiss. It was about respect. Power. Position. And Aria had tried to strip it all away in one move.

“Beautiful night, isn’t it?”

Her body froze. Alexander. His voice was deep, calm, and unreadable. She turned and saw him—sharp tuxedo, perfect posture, eyes hiding something.

“Depends who you ask,” Cassandra replied smoothly. She lifted her glass. “Some nights are more beautiful for mistresses than for wives.”

His jaw tightened. “Cassandra—”

“Don’t.” Her voice was low, steady. “Not here. Not now. You will not embarrass me again.”

He looked at her, something flickering in his eyes. Guilt? Anger? She couldn’t tell. “I warned her. It won’t happen again.”

Cassandra laughed softly, but it wasn’t warm. “You warned her. Not for me. For the press.”

Silence. He didn’t deny it. That silence told her everything.

She breathed in, forcing herself calm again. “Do you know what those women in there are saying, Alexander? They’re waiting for me to snap. To storm out. To cry. They think I’m weak.”

His eyes narrowed. “You’re not weak.”

“No,” Cassandra said, stepping closer. Her diamonds caught the terrace lights. “I’m not. And I won’t let Aria Monroe make me look weak.”

They stood inches apart. Husband and wife. But it felt like enemies.

Alexander finally spoke, his voice low. “Then fight quietly. Don’t give her power.”

Cassandra smiled, but it was cold. “Oh, Alexander. Diamonds don’t break under fire. They cut”.

She brushed past him and walked back inside, leaving him standing there alone.

The ballroom was alive again—laughter, music, flashing cameras. Cassandra slipped right back into her role. She laughed at a senator’s joke, complimented another woman’s gown, even posed for pictures with a graceful tilt of her chin. No one saw her anger. To everyone else, she was untouchable.

But inside, she had made her decision.

If Aria wanted a war, Cassandra wouldn’t just defend herself. She would win. Quietly. Elegantly. Completely.

Her eyes found Alexander again, standing near the glass doors, torn between two worlds. She made a vow right there.

This marriage will not break. Not because of her. Not because of anyone.

I will not be broken.

Not by Aria Monroe.

Not even by Alexander Kane.

At the other end of the room, Aria leaned against the wall, watching Cassandra glide through the crowd like a queen. Cassandra hadn’t cracked. She hadn’t stormed out. She hadn’t cried.

And that made Aria smile.

“Oh, Cassandra,” she whispered to herself. “You’re going to be fun.”

Because a mistress could hurt a man.

But only a rival could hurt a queen.

And Aria intended to be both.