For Donghae , Yoona was his ideal woman , nevermind that she was 4 years younger than him (that isn't huge an isn't it) , but he knew that she was his . 

To him , her choding manner & her alligator laugh attracted him the most . It'd bring a smile to his face every single day without fail. They'd steal tiny & subtle kisses while walking the streets , embrace each other in the middle of a playground & Donghae may spin Yoona 'round & 'round , & no one would mind . 

The both of them would text each other silly messages in the middle of the night , even up till 4AM in the morning . 

Oppa ~ Do you miss me? ㅋㅋ

Of course I do , princess , but why would you ask me such an obvious question? hehe.

Is there a reason to why I can't ask my boyfriend this type of "silly" questions? ㅋㅋㅋ

But I will only tell you that the answer is a definite yes ^______^ *mehrong* .

Text messages like this could end up into heart-to-heart talks & sometimes , they'd stay over at each other's houses , without any caring at all . Donghae would snake his arms onto Yoona's waist & he'd rest his chin on her shoulder , they'd watch a movie , preferably horror movies , but that'll only give yoona the chance to cling onto Donghae , that clever girl . 

But at the end of the day , Both Yoona & Donghae would realise that they've found their perfect other-halves , the one's that they're going to spend their entire lives with . The one's that would take care of each other until death tears them apart.