SCP Foundation

Upon detection, any document infected must be corrected, or reverted to an older version.

"Infected document"

Any person affected by SCP-XXXX's memetic effect needs to be restrained and isolated in a standard humanoid containment cell for 3 days or longer till the effects disappear. Every affected person must receive Class-A amnesics in case of isolation failure.

Second sentence should be "Class-A amnestics are to be issued to the subject in case of isolation failure". Also, you didn't mention exactly what SCP-XXXX does to the affected.

I usually enjoy those types of places, especially ones where you can order a simple cappuccino without having to take a loan.

… and I couldn't resist the urge to look right into those tiny green eyes. And when I did, I knew it was the beginning of a great thing.

"and when I did" what? It doesn't seem to connect with the previous sentence.

We loved each other, for a long time, and the Foundation couldn't even be a threat.

The second clause sounds kinda iffy to me, since the guy is telling about how happy and serene he was with his SO right, but the mention of the Foundation here — plus the word "even" — implies that Foundation did pose a threat to the couple, and that kinda breaks the sentiment of the whole thing a little bit.

Well, I prefer to be honest with you: what I've been searching for since the Foundation harmed me, more than they could've ever wanted, is my soulmate.

What do you mean by "more than they could've ever wanted"?

I haven't heard many things about you, but I already know some of those hobbies of yours, and I love them!

"some of your hobbies"

I was very straightforward, last time, even though it was the first time we'd met.

"straightforward" is too much of a positive trait to be sorry about. Maybe "bold", "eager", or "crass" would do.

For a moment after you just left me, I had terrible thoughts, in that cloudy mind of mine.

Awkward wording. "After you left me, for a moment, terrible thoughts clouded my mind".

I will never thank you enough for answering.

"replying" sounds like a better option.

You see, I was starting to get a little desperate about our whole situation and relationship, and I needed to see you.

Honestly, I think you can just pick either "situation" and "relationship".

Because I have something to tell you: in fact, I wasn't quite true honest to you, that first time we met.

The SCP Foundation, which everyone entrusts with their lives, they took it from me. They made me how I am now.

I might have missed this, but how?

Because that's what triggered our first meeting.

Awkward wording. "Because that was how we first met", or "Because without this form, I couldn't have met you".

SCP-XXXX does not seeem to exhibit memetis properties, but it is theorized the entity is capable of adapting to their interlocutor to make them fall in love.

• typos in the first clause
• What do you mean with "adapting to their interlocutor"? You mean make the people it talks to fall in love with it? And why would it be "theorized", would the Foundation be aware of that by now? Would that be in the description instead, if the document was unaffected?