Something like The K2 it should have a male lead who is good at fighting and also with some romance.
Plus points if its military/secret service/police related like a bodyguard or something.

Dramas I have watched before as an example

The K2

DOTS

When a Snail falls in love

You are all surrounded 

City Hunter/Cruel City

Healer (Korea)

Man to Man (Korea)

General and I (China)

Mr. Sunshine (Korea)

Currently watching The Disguiser and even though I'm only 8 episodes in it pretty much has everything you're asking for. ML is a spy/ military guy who is paired with his life and death partner to have each other's back (romance), and fight scenes as well.

 ShotaSidePart:

Currently watching The Disguiser and even though I'm only 8 episodes in it pretty much has everything you're asking for. ML is a spy/ military guy who is paired with his life and death partner to have each other's back (romance), and fight scenes as well.

Looks like a good drama but the story profile says it doesn’t have romance?

My beautiful bride

Don’t know if this is any good,though

Also check out:

  • The Crown Princess - ML is the bodyguard special forces tasked to protect the FL princess
  • Bridal Mask - ML is Secret free fighter and FL is also a freedom fighter who hates his guts cause she only knows him as a police-dog to japan
  • Iris - ML are both working for korea's CIA
  • Black & White - this is more of male-centric or 2 male leaf drama but they do have their romances 
  • Time between dog and wolf - ML works for korea's intelligence department

Definitely Time Between Dog and Wolf.  Music was fantastic.

1- Always  (cage fighter and it's a movie)

2- Faith  (warrior)

3- Gu Family Book  (kinda warrior, idk) btw historical 

4- Iljimae  (rebel warrior historical )

5- Moon Lovers: Scarlet Heart Ryeo (king-prince fights as always) historical again

6- Rebel: Thief Who Stole the People (was legendary, one of my faves and historical)

7- The Bride of Habaek  (a god trying to be with his lover, there isn't fight scenes as far as i remember)

8- The Last Empress  (i think there is something that you wanna see )

9- The Scholar Who Walks the Night (historical,  and i really don't remember what was the topic but i remember some scenes that you would like to see probably)

note: 4, 6 and 8... i can watch these three dramas all the time... btw maybe you'd like to check on Angel's Last Mission: Love  and Yong Pal.