Nobody has mentioned the j-drama Last Friends yet.
The guy is extremely jealous and possessive, and yet she keeps going back to him.
Yes, this is an extreme case of jealousy where it has gone too far. That's probably not what most people are looking for, but it is the dark and ugly side of "loving" someone so much that you need to control their every move and start panicking as soon as they're five minutes late, thinking they're cheating on you. It happens in real life, sometimes. That's why I don't like to see it in dramas...
I haven't completed Last Friends yet so I'm not sure I know how I feel about recommending it, but it's a good drama overall if you want something dark, sprinkled with some sweet and heartwarming moments - AND it has that jealousy thing.