Forgot the title

It was a promo not sure if it got serialised. I read the novel but later lost the source
The mc transmigrates as the og protagonist’s (who's the ml)villain wife and is older than him. They both were teens?? ig. The ml is a duke and goes to war because it was inevitable. During this time the mc manages the territory very well.
After ml returns mc thinks he will divorce her and marry the og fl which doesn't happen as the ml loves mc deeply but mc doesn't know that .
The ml is orphan from beginning and mc was sold by her family. Maybe she had pink hair. (But I'm not sure about this para)
That's all l remember