from Angel Beats
"..No matter where and how I meet you,
I'll still fall in love with you
If I can meet you again,
against the one in a billion odds,
I'll marry you.."
Yui & Hinata is most probably the most heart-warming couple I've ever seen. A girl who was paralyzed in real-life and a boy who lost his will to play again after losing a do-or-die baseball game; who at first seems to never get along, but at the end still found real love at the after life.
Yui was the replacement singer after the guerilla band Girls Dead Monster lost their main singer Iwasawa. Hideki Hinata was the co-founder of SSS together with Yuri Nakamura, and was the closest guy to Yuzuru Otonashi.
Alongside from Clannad and AnoHana, I consider Angel Beats! to be one of the best tearjerker anime there is. I've just rewatched the episode where Hinata promises to marry Yui in real life and it still gives me the same feeling when I first watched Angel Beats! years ago.
Reason why I picked them for February? Because it's February! And they are my most favorite couple.