You might like watching this 50-episode Historical Chinese drama “Singing All Along”.... don’t let the title fool you (it’s in no way or form a musical drama). 

 SPOILER ALERT:  (Pls feel free to continue  reading below if you don’t mind reading some of the plot). This is a story where the ML became the emperor and the story spanned  from the time when the OTP first went through so much together to form their dynasty/empire.... they  married,  separated, then reunited again,  watched their children grow,  saw their grandchildren, too, at the end of the drama. There was a triangle when he entered a political marriage for power and royal succession at a time when he was temporarily separated from the FL .  But it is not considered a real love triangle because he was very much in love only  with the FL in an “I cannot live without you” way,  and  afterwards he summoned the FL to the palace as his royal concubine.  This is a good example why women should never marry a man who is in love with another woman (I can only  imagine what Princess Diana must have felt about Prince Charles with his then mistress but now current wife  Camilla) .... he lavished the FL with all his love and attention while he is cold toward his neglected empress and a total jerk to her... he was so happy and excited when expecting his child with the FL “because it is with her” and favored his son  with her so much, while he doesn’t even touch or hug his first son with the other woman, and only talks to her coldly and sometimes even harshly.  He always brings his beloved concubine to all his war expeditions and long trips while the empress is left behind at the palace.   He protects her like a precious treasure so no one can harm her even if the villains plot against her.  He was so scared of her dying before him that he even told her he would want to die before her.  During some misunderstanding and the FL ran away from him, he eventually found her and refused to leave her until she went back to him,  declaring that he wouldn’t let her go and would pursue her to the ends of the earth if needed.  Suffering from that kind of frustration, envy, jealousy, and neglect it’s no wonder the empress  plotted endlessly with her mother and brother other until the emperor had had enough and dethroned her. He had always wanted the FL to be his empress so he got what he wanted and dreamed of. 

Legend of Concubine Zhen Huan- It takes awhile for the love triangle to happen tho