Smart lead , romance, team and action

Happiness came to my mind instantly. The romance in it gave me all the feels and it was really nice seeing the leads work together to save people. 
There's also Abyss, which is great! It's really unique and the leads have amazing teamwork and chemistry.
In case you've not watched it, While You Were Sleeping also relates very much to the theme you asked for.

I've watched blood. I like the concept but feel that something is lacking and a very unsatisfying ending. I was also looking for something similar to that but better. 

Anyway, I'll just recommend these coz they're my favorites. Flower of evil and W two worlds. They got some action and love the romance. Start up was good for a smart couple working together, i love there teamwork. 

Fall In Love is so good. It was my first chinese historical drama and it worried me that it would be too heavy or boring to get into it, but quite the opposite, I was so hooked.  The main lead couple is to die for. The budget for the action scenes is very bad, but I still enjoyed the way they solved their problems together.

Flower of evil and Undercover come to my mind, also Graceful Family