Before either notices, January becomes February. If they were a real couple, Luce might have been planning an especially nice dinner or something. Instead, he watches other couples lost in their own worlds of planning and affection. Not to say he didn't get quite a few gifts of his own. The package containing his favorite chocolates and three bundles of the ultra-soft, multi-colored yarn the sender had known he'd been eyeing arrived on the 13th. A bouquet of all his favorite flowers was delivered the next day with a note. "To the one who always cares for others, a reminder to spoil yourself sometimes." Lucius knew exactly who had sent these presents as he gently set the vase of flowers on his nightstand with a light smile. The unexpected delivery had actually caused him to forget for a moment that Sato was over to study. Not like it mattered. It's not like there was anything for him to get jeal- 

Luce looks over to see the man looking sadly at the flowers, his eyebrows slightly furrowed as if thinking hard. "Sorry about that, Shi-shi. We were going over question twelve, right?" 

"Today is Valentine's Day." 

"Yeah, so?" 

"And someone sent you flowers. Not to mention, the chocolates you were eating when I first arrived."

"What are you trying to say?" 

"You should be spending the day with your boyfriend instead of with me... You weren’t dating when we first met so that means it’s still really new, right? That makes it all the more important that you spend enough time together so he doesn’t feel ignored."
"They're from my brother. Our birthday is later this week so he always sends me flowers for Valentine's Day. Said he should make sure I get something since I don't have a partner to send me anything."

"Why had you not mentioned that your birthday was coming up soon? I could have gotten you a gift..."
"It's fine, really. You've paid for all our outings together and bought me plenty of gifts.... If this is how much effort you put into a fake relationship, honestly I'm jealous of whoever you decide to be with for real." Sato gets quiet. Great, Luce made things weird, didn't he?
Finally, Sato spoke up. "... I am the one who should feel jealous of your future partner. I really am not what one would consider 'a catch'... Too cold and not enough ability to pay attention to another person's desires and emotional needs." He looks almost sadly at Luce in the eyes. "In opposition, you have those qualities in spades. You take everyone's feelings and well being into account, and put it before your own wants. Welcoming, friendly and warm to every person you meet even in passing... People naturally gravitate to you without you even doing anything. It is clear that you will make whoever you spend your life with the happiest man alive." 

Luce's face reddens with a mix of thoughts and emotions, but the one that he blurts out probably isn't what either of them expects. "Then where the fuck is he? No one actually wants me, no matter how many supposedly desirable traits you think I have."
Sato moves closer. "Just because you have not found someone worthy of you does not mean he does not exist. I am sure you will meet him in due time. We are still young so there is no need to be giving up so early..." He places a comforting hand on Luce's shoulder. 

Lucius sniffles and wipes nonexistent tears away. "And you think you're not attentive and caring, Charmer... You don't even like me that way and you're taking care of me. I can just imagine how you'd act with someone you actually love." Sato freezes.

 "Guess that class last semester did actually help, huh?" He gave a nervous chuckle.
His out of character behavior causes Luce to look at him worriedly. "Satoshi?"

"I... Sorry." He starts to pull away, but Luce grabs his hand. He doesn't know why, it feels like if he lets him go, Sato will disappear forever. 

"Shi-shi... What do you have to be sorry about?" 

"Having you be my fiance, I am keeping you all to myself instead of considering how it might affect your chances to find someone who you can love for real. I should have just let my grandmother arrange a union for me... This is just keeping you from someone who deserves your affection." He can't seem to look at Luce. "I am nothing but a selfish child."
"I agreed to this too... Are you regretting asking me to help like this?" 

"No! Yes? I do not know.... There is no way that you could be happy in this situation. You deserve to be doing all those things we have been doing these past months with someone you actually love... I..." 

"Deserve the same yourself. You're not the one using a fake engagement to get closer to your crush and monopolize them." Luce is so focused on comforting Sato that he doesn't realize what he's admitted.

 Sato seems to have, though, as his eyes get wide. The next moment, Luce finds himself suddenly being kissed. He melts into it as the shock wears off.

When they part, there is an odd silence between them before Sato breaks it quietly. "... Sorry. I should have asked permission first." As if Luce would have denied him when wanting to do the same time for so long... "You are wrong, though. I might have not fully understood why at the beginning but I kept suggesting we make the ruse more involved and elaborate because I wanted it to be real." With how softly he spoke, one wouldn't expect to be able to hear him when his voice gets even quieter, but the stillness amplifies every sound somehow. "I want you..." He looks so vulnerable, as if Lucius' rejection would destroy him.
"...I want to be a father more than anything." 

"I am aware." 

"I can be quite overbearing and smothering, especially when I think someone isn't taking care of themself." 

"All the better when it comes to me." 

"We'd essentially be skipping the dating part of the relationship." 

"Dating was never my strong suit anyways."

 "We'll have to tell your parents it isn't fake anymore..." 

Sato smiles. "They thought the fake engagement was a bad idea, anyways, considering my feelings for you." 

"We're both idiots, aren't we?" 

"Yeah. We probably are." 

Luce looks at the flowers that started this whole conversation. "I should probably tell my family as well, then... Let my brother know he doesn't need to buy me flowers every year anymore. I have a partner to do that from now on, afterall." He looks to Sato. "Right?" 

"I will likely need to set myself a reminder until I make it a habit." He takes both Luce's hands in his own. "And it simply will not do for me to not know my partner's birthday. I will need to put that on my calendar as well." 

"The eighteenth, ten minutes before midnight to be exact... Our mom was in labor so long that my twin brother and I ended up with different days on our birth certificates." 

"Then I will be sure to always remember it going forward..."
Four days later, Satoshi made a strong step towards continuing to make good on that promise. Dinner at Luce's favorite local cafe - "Birthday boy is not allowed to pay" - and a small wrapped gift while waiting for dessert. When he opened it, Lucius had to physically pinch himself to check he wasn't dreaming. The exact ring he had been trying to pretend he didn't want when they'd gone ring shopping before sat majestically inside. 

"...We told my family you had already bought me a ring before I proposed, but I want to really propose properly now so it was my turn to buy you a ring this time."

Luce puts it on, still not fully believing this is all real. "Your multi-slide presentation on why we should get married would likely be inconvenient to do in the middle of the cafe, so I'm going to skip to saying yes and you can show me the whole thing later when it's just the two of us."

Luce decides there are some sides to his partner he doesn't feel like sharing with anyone else. This wildly affectionate side would solely be his... Til death do them part.