I honestly can't keep reading this, it's great!! But it's not for me :/. I think Siwon doe...

Yeah, well, "the guy" is spending money that's Siwon's while Siwon is eating scantily. Both of them can be pretty dumbass. Though Siwon is moreso.

The guy thought he bought it while he was drunk.

Also technically finders keepers

I'm not buying that crap. He remembered having sex but he has no receipt or anything for the ticket. Naw. Plus when you live with someone, you get used to habits. Was he in the habit of buying it or was Siwon in the habit of buying it? In our household, my guy never buys them, I sometimes do. And now that he knows Siwon WAS in his room and did have sex and suddenly, whoosh, a ticket. Sorry, he took Siwon's money. But I like him. He's a sweet guy and should have had the benefit of the doubt over the bedroom scene.

He didn't technically remember having sex. He thought it was a dream and only figured it was real because of the marks that were left.

And who the hell takes the receipt of things they buy? Especially if they're drunk.

He already knows he had sex and Siwon was in the room the night before when he found the ticket. He himself was surprised he found a ticket. He should be realizing it may not have been his.

With all the shit that's going on right now, do you think he'd be thinking about the lottery ticked of all things?
Especially when he spent the money already?

Yes. Because that was a shitload of money if he could buy a WHOLE DAMN building with it.

Didn't he buy the building with the money that other guy lent him as well?

And if his boyfriend was so concerned about the money he could've asked him about the lottery ticket that he vouchy completely consciously.

No, I think he asked the guy to lend him the money until he cashed out and got money from the lottery.