I've been there before and it turned out to be one of my favorite tropes.
You may like it - no major spoilers, it's all from synopsis:
You Are My Glory (2021) [FL falls for ML at highschool, he rejects her. Later on, she's grown into a famous actress and he is in the middle of a career crisis. He meets her again and realizes how she really is and how he was wrong about her before]
I May Love You (2023) [ML brutally rejects FL. He regrets a whole lot and chased her with all he had]
Everyone Loves Me (2024) [ML rejects FL, only after that he discovers that she was his online crush and tries to win her back]
Renascence (2020) - ML is in love with the queen, who's married to his brother (the king). FL is killed but her spirit enters in her younger sister's body. ML doesn't know and even still loving the queen he likes her sister as well (who is also the FL)
The Last Immortal (2023) - Due a misunderstanding, ML loves a woman that never loved him back. Meanwhile, he meets FL and starts to develop feelings for as well.
The Legend of Anle (2023) - ML promised to marry younger FL. Due to destiny, they separated and lived different lives. He meets FL again but doesn't recognize her, since she goes by another name. He still waits for "younger" FL to appear and marry him, but he also likes the woman in front of him.
Alchemy of Souls Season 2: Light and Shadow (2022) - It has part 1. I recommed to start from there. BUT, ML lost his only love and by some situations he ends up in a marriage-like situation with FL. He loves his ex-lover with all his might, but FL also make him go soft.
Find Me in Your Memory (2020) - Slow burn. ML was very in love with FL best friend years ago and she vanished. Years later, he meets with FL but she lost her memory. He is haunted by his past feelings and the burden of knowing the connection between him and FL, but can't stop also needing to protect her.
Heartbeat (2023) - ML is a vampire. He loves one woman for 500 years. In the present, he meets FL and a woman exactly like his past lover. Even still having feelings for his ex-lover, he can't let FL go.
Hidden Love (2023) [I recommend it for everyone, still haven't seen someone hating this. FL has a crush on ML since highschool, but ML is older and never saw her as a woman. Until they meet again, and he realizes he'll have to chase her to make her believe his feelings]
Itaewon Class (2020) - Very slow burn. ML loves his childhood sweetheart for years. Even still loving her, he meets FL who became necessary to him.
My Man Is Cupid (2023) - ML fell for a woman who died 500 years ago. Ever since, he "reincarnates" and ends up falling in love most of the times, wich ends up in tragedy. Now, never letting go of hispast loves and the burden of tragedy, he can't help but being near FL.
The Forbidden Marriage (2022) - His ex-wife died and he loved her a lot. It's weird for him falling for another woman.
The Legendary Life of Queen Lau (2022) - ML has to marry FL but dislikes her 'cause he sees her as "ugly".
The Love by Hypnotic (2019) [FL is a princess who gets married for political reasons and both FL and ML don't each other at first. Later on they fall, but FL forgot important parts of her past]
Romance of a Twin Flower (2023) [FL enters a tricky situation: she's confused as another woman identical to her, but EVIL. This evil woman has a husband who hates her guts. So FL have quite a journey until ML lets go of his hate to realize she has "changed"]
Different Princess (2024) [BIT of supernatural since FL goes to fictional past, but FL ends up married to the villain, so she's scared of him and they don't like each other]
Destined (2023) [ fits your description: leads get married but don't actually like each other, later on they end up falling]
See You in My 19th Life (2023) - ML falls for his childhood friend, not able to fall for anyone else ever since her death. Then he meets FL and even still longing for his old love, he can't help being attracted for FL. time during the marriage]
A Girl Like Me (2021) [been some time since I've seen it, but shows the leads falling, being engaged and marrying, but ML is not very trustworthy]
Dramas in which ML lies / treats FL bad and later on, regrets trying to win her back:
Jinxed at First (2022)
Back from the Brink (2023)
Crush (2021)
Strangers Again (2023)
Love of Thousand Years (2020)
You may also like it:
Suspicious Partner (2017)
Love Destiny (2018) [Bit of supernatural: FL goes to the past. FL assumes the life of a recent dead woamn identical to her, but very EVIL. This evil woman has a husband who hates her guts. So FL have quite a journey until ML lets go of his hate to realize she has "changed"]
Padiwaradda (2016) [FL is grateful for the family that raised her. She accepts to get "swapped" to marry her sister's fiance. ML knows since the beggining and hates FL for lying to him, but FL is very sweet. It takes a while for him to forgive and admit his feelings]
Kleun Cheewit (2017) - FL is accused of killing ML fiancee, so he hates her with all his power; trats her REALLY bad. But, he can't help being attracted to her and after seeing how she truly is, they fall
