Scarlet Heart: Ryeo,
Female lead is in love with another character at first, they promise to marry each other if he gives up his greediness > circumstances led to her not marrying him and falling in love with the male lead. This is maybe what you are looking for?
Duangjai Akkannee
Female lead and male lead develop feelings for each other despite knowing that their families will not agree to their relationship > female lead father keep pushing another guy in her life and wants her to marry him > she does not like him and some things happened that made her relationship with the male lead possible.
Sarm Noom Nuer Tong
Well there are actually 3 female leads and 3 male leads in this drama, but 1 female lead has a boyfriend and is super faithful to him while her boyfriend is really abusive and likes to sleep around. Male lead keeps liking her and his friends ( the 2 other male leads ) try to find opportunities to get these two together. The female lead was not married or was planning to marry tho.. I think, I don't remember it anymore.
Ton Rak Rim Rua
This drama is a bit different then your description tho. The female lead was already married to the male lead because of a request, divorced, married again because of work problems, I don't remember if they divorced again and married for the 3rd time later on or that they never divorced after the 2nd marriage. But after the 2nd marriage female lead began to like a coworker > was planning on marrying him > changed her mind and came back to male lead.
The last 3 are thai drama's and the first one is a korean drama. I hope that my recommendations are the types you are looking for~