The male lead helps the female lead get with the guy she's in love with...

• I Need Romance 3
• Wednesday 3:30 p.m.
• Oh My Venus (rather than helping the FL get back together with her ex, he helps her lose weight partly because of her ex but mostly for herself + for her health but it has similar themes so I thought I'd include it)

There is High School Debut (manga and Jmovie), but the guy coaches the girl to become attractive to have a boyfriend.  

The only drama I can think of would be Weightlifting Fairy Kim Bok Joo.

Wednesday 3:30

Let's Eat 2

Personal Taste

Similar theme in Marriage, not Dating

Thumping Spike II

bonus: movie Like for Likes has a theme like that, too, with one of the couples