No need to worry bout plum blossom girl, there's no romance between them. But he will get married with his disciple, and the romance is barely there.
In the Romance of the Three Kingdoms, which this webtoon is based on, it really focuses on the politics and action, loyalty and sworn brotherhoods. Women are mostly only mentioned fleetingly as this and this wife got captured, gave birth, etc. and really doesn't have a big role, so there's not much romance to speak of unless you rule out "bromance."
*Unless you consider "bromance" as the romantic bit
My instinct keep telling me there is romance in this manwha even though they said it does not any romance. I stop reading at chap 90. I’ll come back for it later. So far, it is a good manwha. I just disagree about one plot where the plum blossom girl fall in live with a teenagers that is barely 15 y/o. Isn’t that pedophile?