If you watch Taiwanese dramas then
Autumn's Concerto should fit your taste, even if is full of cliches it's still enjoyable. There's also
Hi! My sweetheart, is a lighter drama than Autumns Concerto, and also full of cliches, but quite nice to watch.
Can You Hear My Heart, is a really cute drama, but I'm not sure if it counts since they weren't exactly lovers but childhood friends (well the boy did have a big crush on her) and they weren't in any relationship per say... ¬¬
Operation Proposal, okay this one doesn't exactly fit the profile, because they are not physically separated, just the timing is reeeeeally bad. But she is marrying someone else even if she still likes him, and he's trying to get her back by changing the past, is a great story. I prefer the korean version, but you can also watch the original
Proposal Daisakusen
Winter Sonata This is without a doubt a great fit, they loved each other deeply but because of a lot of set backs they part, and when they finally meet, he is dating her friend and she's about to get married! I'll be frank, I don't really like this drama, it feels like it takes too much turns, and is too slow, but a lot of people seem to like it, so maybe is worth a try
