Donghae and Hyukjae get married. I'm pretty sure it's an arranged one. But Hyuk already has a girlfriend that he keeps seeing. 

Donghae finds out he's pregnant and about Hyuk's mistress so he moves out to his own house. They keep their separation a secret from their families though.

The only doctor qualified to deliver the baby is in New York and Hae is arranging everything to go. Hyuk realizes he loves Hae, drops his mistress and tries to reconcile.

They end up moving to New York together and have their kids. I know there's a part at the end about them biking in Central Park.

Anyone else remember this?

A big thank you to tleo_03 for finding this.

Perfecting our Imperfections - Asianfanfics