Notes From Reviewer

Title 

I didn't read every chapter (I skimmed the remaining ones) because I got the basis from the ones I did read and so far I don't see the connection in the title to the story. It's just kind of there. Sure, at first glance it's very nice indeed but after reading, you wonder what the real point of it is besides it sounding nice.

Description & Foreword 

One thing I didn't get is in the description you say "Jiyong never liked the fact that his girlfriend" but in the first chapter, they're married. So she's not his girlfriend, she's his wife. Also since they're married, shouldn't she be addressed as "Kwon Taeyeon". not Kim Taeyeon? Besides this, the description was okay. It told you what was gonna go on throughout the story so that is good.

Plot

The plot is kind of cliche and I think everyone saw the secretary thing coming because that's used so damn much at this point. I really just wasn't surprised. Also most emplyers don't want people in relationships to cause problems and will not let them work together (my co-worker had told me they didn't let her work where her boyfriend/now fiance worked because it could cause issues) so the realisitcness of this is pretty off by miles. Yes people hire them sometimes but if there are problems at home, it could sometimes lead to work and be disruptive just like Jiyong not wanting her to be there (or whatever that outburst was). That's a GREAT reason to why people hate hiring couples.

Writing Style 

In the first chapter, you said "...that her husband burrowed money" The word burrowed means to make a hole.
Instead of burrowed, it'd be borrowed. Like he borrowed a load of money. So it would be "...that her husband borrowed money"

Some of the character dialogue is weird. Example would be:
"Aigoo... You still don't know how to button your shirt?" Taeyeon chuckled looking at the flustered Jiyong who turned to the other side upon seeing her. "I c-can do it myself." 

Since there are two different characters talking, the dialogue shouldn't be smushed in the same paragraph. It would be like this, seperated:
"Aigoo... You still don't know how to button your shirt?" Taeyeon chuckled, looking at the flustered Jiyong who turned to the other side upon seeing her.

"I c-can do it myself." 

Everytime a new character speaks, they should be put in a seperate place. I've noticed you did this a few times. It's kind of not good to have it like that because sometimes it's hard to understand who is talking. The only reason I know who is talking is because of Jiyong's... stutter? Or whatever is up with him. Either way, they should never be smushed together that way.

Also, after the word 'chuckled' there should be a comma (,) because then it just becomes a weird run-on sentence without it. 

Aside from these few errors, there are some other things I find odd. Like this: "[...] Seunghyun said- trying to sound understanding." Why are there so many '-'s' everywhere? This just is awkward and it really shouldn't be there. 
I'd get rid of it so it's  "[...] Seunghyun said, trying to sound understanding." Get rid of the - and put in a comma. It flows better that way. 

In chapter/episode 3, you put in a physical picture of Taeyeon which usually is a no-no in story writing. Describing what the character looks like makes it much better and just adding in a picture makes it seem like you don't know how to do that. I'm not saying you don't, of course, but you're giving off that impression. In a real book, they don't really use pictures (there's the special occasion but it's very rare in a non-childrens book but they never smack it right dab in the middle of the story).

The use of romanized Korean words is also kind of cringe-worthy. Also "Anniyo" isn't spelled like that. I study Korean in my free time and it's 아니요 (aniyo). 
아 a
니 ni
요 yo

This include the words "Oppa", "Arraso" (which is spelled wrong, it's spelled as Araso if you used romanized, which you really shouldn't), "omo", and whatever else Korean word used.

For 알았어 or 알았어요 (the first one is used for someone who is younger than you. It is not polite to use this version if you're a younger person speaking to an older person. the moment you omit 'yo (요)' it becomes talk for someone who is younger than you.) Taeyeon is younger than GD (I had to look that up - GD is 28, Taeyeon 27 so it's considered rude for Taeyeon to use that version because Jiyong is older so using "Araso" is rude).

In Episode 4, you said "You're wife wants to show off her legs"
You're means you are. "You are wife wants to show off her legs" makes zero sense. Your is the correct version to use and it's ridiculous how much people misuse this word (even English speakers can barely use it right - it's just sad). "Your wife wants to show off her legs." 
So You're means you are and Your is like possession. E.g.: "Your cat is a moron." The cat is mine, so therefore you'd say "your cat".  

Again, using pictures isn't the way to do things, explaining them is the better way. Pictures can be very annoying in stories.

You spelled Leeteuk wrong. It's not Lee Tuek, it's Leeteuk.

Characterization 

When reading the first chapter, I don't really understand why Jiyong stutters so much. Does he purposely have a stutter (as in he was born with it and cannot control it) or does he really just have terrible anxiety? Also, Jiyong is a male and honestly men shouldn't giggle in fanfics, it's a common theme I've noticed but it's just kinda cringe-worthy in my opinion. He shows a lot of love for Taeyeon which is cute. 

Taeyeon is generic, nothing really pops out about her besides the fact that she is the "man" in the releationship really. That's probably the only thing that sticks out about her. You can tell that she loves her husband, yes, and would do anything for him (well, mostly) but not much else. Really wondering why Taeyeon would use her maiden name when she's obviously married? I think it's a bit of a move on her part. I would be pissed if my partner used their maiden name and we were married too so I can see why he got so mad.

Flow 

The flow is awkward because of all of the -'s put in. I feel like the only time time the - should be used is in dialogue, or in the story if deemed realllly necessary, because it seems like someone is getting cut off during a talk.
Example:

"What the f-"

"(random text here)"

So the first person got cut off by the second which is where that seems more appropriate. When you do it in "[...] Seunghyun said- trying to sound understanding" it just sounds like you stopped the sentence after said then awkwardly tried to resume it.

Personal Enjoyment 

I'd say the biggest issue is the grammar/writing style because there were a lot of small mistakes, plus the ones I pointed out, and the Korean words are really cringe-inducing. If you don't speak Korean, and if you do - you wouldn't be using romanization - you'd be using hangul - don't use it. Honestly, it's just not good and plus you spelled them wrong in most cases. I study Korean as I said before and I just kind of facepalmed. Tip would be to go through the fanfic and take out the Korean, it makes you seem like a Koreaboo. Most K-pop fans just want to go to Korea to see idols, they don't care about the culture or just want to learn the language to talk to their, God forbid I say it, "oppas" - some really do this and I'm not saying it's you, I've just really met people like this - and it's not good. The only time Korean should be used in a fanfic is if the story is Korean and if it's in Hangul (or if a Korean poem, etc. is used an translated under). Maybe hiring a beta reader/editor could help you fix the errors within it but there's a few within each chapter.