Endgame Pairing is Not Obvious

FL is in love with someone else at the beginning

FL marries another man but ultimately ends up with the ML.

FL is married and divorced from someone else at the beginning

FL has an ex boyfriend

ML was engaged

FL has an ex girlfriend

ML has traits of a SML/secondary villain

ML has an ex boyfriend

FL has an ex boyfriend

everyone is involved with or in love with everyone, endgame is not clear until the very end

SML gets the girl

SML gets the girl, FL is in love with and pregnant by the ML at the beginning

FL is married to someone else at the beginning

FL has an ex fiancée

love triangle, SML is given scenes/tropes with the FL commonly given to the ML

ML is FL's second love, and she marries someone else before ultimately ending up with the ML

FL was married to the SML

FL is married to someone else at the beginning, ML has traits of a SML

FL is a widow

FL is engaged to someone else at the beginning

ML has an ex girlfriend, ML has an ex boyfriend

heavy love triangle that could go either way

FL was in love with the SML

FL is divorced

ML had a wife in the past and is torn between her reincarnation and the FL in the present

love triangle, FL has the childhood connection trope with the SML

FL is married to the SML, then falls in love with the ML

FL has a girlfriend in the beginning

ML is engaged

FL was childhood friends with and originally expected to marry the SML

FL has a boyfriend and is pregnant by him, ML has a fiancée, but they end up together

FL is married and appears to end up with SML at the end

FL is dating  someone else at the beginning

FL has a long crush on someone and accidentally confesses to the ML while she's drunk. Her crush re-enters her life later on but she ends up with the ML.

FL has the past connection and first love with the SML (and actually only approaches the ML because she wrongfully believes he has the SML's heart transplanted into him)

FL is married

ML had an ex-girlfriend he's still heartbroken over

FL is married

heavy reverse harem, FL is in love with someone else for a long time and was married in her past life, ML is an atypical protagonist

ML is in love with another woman at first

ML has a girlfriend

heavy love triangle, FL appears to love the SML more for much of the drama

heavy love triangle, FL is dating SML for much of the drama

ML has a first love who returns

ML is a widower with a daughter

FL is married/divorcing

FL is married to someone else at the beginning

heavy love triangle, ML is atypical protagonist

ML is in love with another girl before and for a while after he marries the FL

FL was married

FL was married in her past life

love triangle that could go either way, FL has the childhood connection trope with the SML

heavy love triangle, FL is initially engaged to the SML 

FL is married to someone else at the beginning

FL has the childhood connection trope and engagement with the SML, heavy love triangle

ML had a former first love who he planned to marry until she died

love triangle between FL, the human soul of ML's body, and the dragon possessing his body

SML gets the girl

love triangle, ML dates both the ML and SML

FL has an ex boyfriend who died

FL is initially close to and engaged to the SML

FL was engaged to the SML in her first life

ML is in love with someone else for a long time first, FL has traits of a SFL at first

FL was married 

FL was originally in love with the SML

ML has an ex boyfriend

ML had a first love who died, and at first it seems he's just settling for the FL due to her resemblance to his lost love

love triangle in which FL loves the ML but appears to end up with the SML

FL is initially the SML's mistress and the ML is her employee who is secretly in love with her.

FL is a divorced single parent

FL is intially in love with the SML

ML has a boyfriend

FL is engaged at the beginning

ML has an ex-boyfriend who died

FL has a boyfriend

FL is a widow

FL is initially in love with the SML, ML has traits of a SML

ML is divorced

FL has an ex husband

FL has a long time crush on the SML

Reverse harem, love triangle with childhood friend

FL has an ex boyfriend

ML ends up with SFL, despite having the childhood connection trope with the FL

FL is dating someone else at the beginning

FL used to date the SML

FL is married to someone else at the beginning

ML has a girlfriend

FL was engaged

heavy SLS, FL has a first love who is a ghost/in a coma and for a while it's unclear whether she'll have a second chance with him or choose the ML

FL is in love with ML's brother

ML has a fiancée at the beginning and wavers back and forth for a while before choosing the FL

FL is dating someone else at the beginning

heavy love triangle that leans toward the SML who the FL is dating