Mirai was getting paid for his "services"
Like in the beginning of the chapter how the characters on the TV were having a clean split, and the guy payed her. ( ̄へ ̄)
Hm, maybe also because a letter could be used as "evidence"? *disgusted face* A creep will be a creep....
I's a way to crush someone by tell him : What he was for you "a hole". What a bad guy =凸 But the uke is stupid too... It's not because he want to get lewd that he have to follow anyone ┑( ̄Д  ̄)┍
I didn't understand the money envelope part ._. why money? a letter would be more idk... suitable?