Well, mostly the romance was just a subplot, but here my suggestion:
Battle of Changsha
Legend of Zhen Huan
Three Kingdoms 2010 (based on the wisely popular Romance of Three Kingdoms, the more faithful-to-the-book vers would be the 1994 released version. I myself haven't read the books so I enjoyed this version pretty well)
The Young Warriors of Yang Clan
Or if you're in the mood for something where romance is the focus of the story:
Palace: The Lock Heart Jade (similar to Scarlet Heart, but more lighthearted)
Prince of Lan Ling (kinda dumb female lead, though)
Princess Pearl (it has been a long time but I don't recall the female lead to be smart lol)
Introduction of the Princess
Mu
As far as I know the male lead in Female Prime Minister was a one-woman man, alas I haven't finished it, but I'm pretty sure at least he won't love another woman even though he eventually has concubine/s. I'm not very literate in Chinese history so I have no idea whether this drama is based on real historical event or not.Anyway I don't think the other forum members know that many of chinese dramas, the particular genre isn't really popular here perhaps because the lack of english subtitle. Maybe they're taking a peek at your thread trying to look for recommendation as well, lol. I myself was just looking around chinese drama forum every now and there trying to make my chance to recommend Battle of Changsa, that drama was so painfully underrated. Know its existence, people! Watch it already!