nakanmon! I really liked this one
and tonari no atashi but someone already suggested that, also, one of my favourite webtoons: Cherry boy, that girl

Quote from SilverStorm

How are you defining first guy? 'Cause it's quite clear from the beginning in Hana Yori Dango who was "main guy." It's called "Ji-hoo syndrome" for a reason...

Actually he wasnt... She changed it midway as she was writing it when she realised more fans were rooting for tsukasa.

Venus wa Kataomoi

It started like a cliche shoujo manga, but into the second volume it will be very unexpected, and the story ending leaves you with a warm happy feeling that make you just want to go out and do some good deeds and be happy for doing them. Definitely recommended. 😀

Edit: I sincerely hope that this has been translated into your language, or you can read Japanese, since it appears not completely scanlated.

If anyone is still interested, here is one completed series where the girl ends up with the secind guy: Hirunaka no Ryuusei

Also: Tonari no Atashi

I'm in idol hell T.T