Amid the professor's lecture, Chae-yeon sat in front of Si-hyun, biting her pink lips anxiously.

‘A couples ring? How is she doing something I never got to do!’

A couples ring is practically a symbol of a relationship, an item for couples that strengthens their bond and builds trust simply by wearing it.

But to think Si-hyun and Ye-rin were wearing that precious item together?

The thought that Ye-rin, who had only been dating Si-hyun for a few months, managed what Chae-yeon hadn’t in over a year brought a creeping sense of inferiority to Chae-yeon's heart.

‘No, if it weren't for the trauma, I could have progressed faster too.’

Chae-yeon believed that without the trauma, if she could have been honest with herself, she would have achieved not just a couples ring but physical closeness with him as well.

Trying to mentally convince herself and shake off her feelings of inadequacy, Chae-yeon's focus was broken by Ye-rin's voice reaching her ears.

"Come to think of it, Si-hyun, isn't your birthday coming up soon?"

Chae-yeon's eyes widened in surprise. She quickly checked the date on her phone.

‘Today is September 1st... only three days left!’

Despite living like a recluse and losing track of the days, how could she not remember Si-hyun's birthday was so close?

While Chae-yeon grabbed her hair in self-reproach, their conversation continued.

"Yeah. It's impressive you remembered."

"Of course, I would never forget something about you."

At Ye-rin’s affectionate remark, Si-hyun smiled. Ye-rin, with her bright smile, tapped the desk with her fingers.

Then she asked in a gentle voice.

"You don’t have any plans on your birthday, do you? If you're free, how about going to a nice restaurant with me..."

"Sorry, I already have plans that day."

"What?"

Ye-rin narrowed her eyes sharply and then spoke in a cool voice that could drop the temperature in the room.

"Birthdays should prioritize a date with your partner. Who on earth are you meeting?"

Ye-rin, determined to make him cancel whoever it was, was on fire.

"My parents."

Realizing that the person he was meeting was his parents, Ye-rin backed down immediately. To her, they were the creators who gave birth to Si-hyun.

For the sake of her future marriage, it was crucial for her to earn their points.

"Ahem!"

Clearing her throat, Ye-rin opened her eyes wide and spoke.

"Si-hyun, can I come along too? It would be nice to greet your parents. I want to visit them after such a long time."

At Ye-rin's request, Si-hyun nodded.

"I was actually going to suggest that. My mom called yesterday, insisting that I bring you along..."

"Your mom wants to see me?"

When Ye-rin asked with a puzzled look, Si-hyun responded with a light sigh.

"She saw our profile picture and realized we were dating. She said, why didn’t you tell me yet? When is our new daughter-in-law coming over? The way she kept talking..."

"Hiccup!"

Sohui let out a loud hiccup and hurriedly covered her mouth. Many students' eyes turned towards her.

'New daughter-in-law...'

Ye-rin was busy daydreaming happily.

'New Daughter-in-law.'

It's a term in-laws use affectionately to address a son’s partner.

Perhaps the years of building a relationship since childhood had paid off, and Ye-rin's face softened with delight at being acknowledged by Si-hyun's mother.

"Puhuhu... She calls me the new daughter-in-law."

"Do you like being called the new daughter-in-law that much?"

Ye-rin nodded enthusiastically.

"Of course! They say other girls struggle with their mothers-in-law after marriage, but I'll never have to worry about that."

"Even if you did, I'd take care of it."

His sweet words seemed carefully chosen.

Ye-rin playfully pinched Si-hyun's cheek as a sign of affection.

"If I'm the new daughter-in-law, then Si-hyun, you're the husband?"

"Geez. People would think we've already set a wedding date."

"Why not~ If your parents have acknowledged us, it means we could get married anytime."

"At least finish college first. Plus, I haven't completed my military service yet."

When Ye-rin heard he hadn't done his military service, her cheeks turned rosy. Rubbing her hands against her thighs, she whispered daringly into Si-hyun's ear.

"Si-hyun, they say if you have a child, you can switch to less demanding duty..."

Si-hyun was left speechless by Ye-rin's provocative suggestion.

As the two continued their playful exchange, expressing their affection for each other...

'New daughter-in-law... New daughter-in-law...'

Chae-yeon was overwhelmed by the fact that Ye-rin was even familiar with Si-hyun's parents.

'I've never even met Si-hyun's parents, nor heard their voices...'

What had she been doing in the past? She had grown so accustomed to only receiving that she lacked knowledge about Si-hyun and had few experiences of doing well by him.

'I'm truly the worst...'

Chae-yeon felt the growing gap created by time—the 15 years spent by a childhood friend, compared to her single year of immature demands.

With Si-hyun's affection waning, Chae-yon had slim chances of turning things around.

'I wish I could just ask to go with them...'

Chae-yeon imagined herself begging Si-hyun's parents for their son, until her hands were sore from pleading. But she knew Si-hyun would never take her along, and following them by force would only bring scorn.

'There's no other choice... During this time, all I can do is look for a gift for Si-hyun.'

With this resolution, Chae-yeon took an eraser from her pencil case. She gently nudged it off the desk to make it fall to the floor.

"Oh, I dropped my eraser..."

With this awkward bit of acting, she bent down, and as she picked up the eraser, she glanced at Si-hyun's feet.

'What? He already got new shoes?'

The shoes she had planned to buy for him since the day of their blind date—his worn-out shoes had been replaced by brand-new white sneakers without her even realizing it.

'Even matching with Han Ye-rin's shoes...'

Chae-yeon belatedly realized that the two were even wearing matching couple sneakers.

"Sigh..."

After retrieving the eraser, Chae-yeon, feeling even more defeated, took a deep sigh, realizing the hurdle she had to overcome was immense.

After the lecture ended, it was time for lunch.

Feeling hungry, Ye-rin gently tugged on Si-hyun's sleeve and asked.

"Si-hyun, shall we go to that pasta restaurant we went to before?"

"Do you feel like having pasta?"

"Maybe it's because the semester just started, but I suddenly wanted to go there again."

"There's no reason not to. We're heading straight there, so pack up your laptop."

"Okay!"

As Si-hyun and Ye-rin linked arms and left, Chae-yeon and Sohui followed them.

The two cautiously tailed them, careful not to be noticed. Chae-yeon, hiding behind a utility pole, watched Si-hyun's retreating figure and spoke.

"Sohui, I'm sorry for dragging you into my personal matters."

"It's alright. This isn't entirely unrelated to me... I decided from the start that I'll help you, Chae-yeon."

Chae-yeon, who didn't want to eat alone awkwardly, was accompanied by Sohui as they followed Si-hyun and Ye-rin into the restaurant.

As a result, the two of them ended up tailing in pairs, entering the pasta place five minutes after Si-hyun and Ye-rin.

Ting-a-ling~

Entering the restaurant while chatting with Sohui, Chae-yeon tried to act naturally.

When she spotted Si-hyun in a corner, she initially wore a surprised expression, then broke into a bright smile.

"Si-hyun! You're here for pasta too, huh?"

".........."

"Enjoy your meal, both of you. Sohui, let's order quickly."

Si-hyun blatantly ignored Chae-yeon as she sat at the nearby table, while Ye-rin gave them a meaningful glance, pondering whether this was truly a coincidence.

Gulp. Gulp.

While sipping water, Chae-yeon repeatedly glanced at Si-hyun.

'He's gotten more handsome over the break...'

As she gazed at him with eyes full of admiration, she caught sight of the ring on his ring finger and frowned.

'If I manage to start dating him, the first thing I'll do is get matching couple rings.'

From couple shirts, to couple sneakers, to a long scarf they could both use in winter.

While Chae-yeon was mentally organizing her shopping list, the ordered food was placed at Si-hyun's table.

Not just one or two plates, but enough food to fill the table, including side dishes.

Seeing such a scene for the first time, Chae-yeon blinked repeatedly.

'Is it even possible to eat all that?'

Chae-yeon, unable to imagine Ye-rin consuming that amount, assumed Si-hyun had started eating more. As she stared on in amazement, Ye-rin noticed her gaze and twisted some pasta around her fork, offering it to Si-hyun.

"Si-hyun, say ah~"

In the past, Si-hyun would have felt shy about being fed, but now he happily accepted it.

And it didn't stop there.

"I'll give you some too."

Si-hyun even fed Ye-rin some of his pasta, causing Chae-yeon's confidence to slowly crack.

'Feed me too...'

Images of the past flashed through her mind. Si-hyun used to feel full just watching Chae-yeon eat, always making sure to feed her delicious bites.

"Want another bite?"

"Yeah!"

But those loving gestures now belonged to Ye-rin. The pair created a sweet atmosphere, feeding each other and wiping the sauce off their lips.

Feeling sad, Chae-yeon couldn't bring herself to touch her own food and just watched the two eat.

And Ye-rin, aware of how Chae-yeon felt...

'How do you like that, don't you envy us?'

She continued to flaunt their affection right in front of his ex-girlfriend, intensifying Chae-yeon's heartache.