PLS FRIENDS SUGGEST SOME DRAMA WHERE THE MALE LEAD IS A GOOD GUY. HE HAS NEVER DONE ANYTHING BAD AND ALL THE PEOPLE AROUND HIM LIKE HIM. HE IS ALWAYS THERE FOR THE FEMALE LEAD IF POSSIBLE NO LOVE TRIANGLES 

EXAMPLES, THE K2, HEALER, YONG PAL, INNOCENT MAN.

Hmm the only dramas I can think of with no love triangle would be Descendants of the Sun, Weightlifting Fairy Kim Book Joo and W - Two Worlds. And maybe Doctors and Doctor Stranger could fit your criteria of a good guy being there for the female lead. I guess Pinocchio could suit it too maybe?
Shopping King Louis has the most adorable male lead and a very mild love triangle, if you could even call it that.
Ho Goo's Love
I second Doctors

Jejoongwon
Smile Dong Hae
Smile You
Golden Bride

all of them either have no love triangles or very weak ones.
I made this list awhile ago hope it helps! http://mydramalist.com/list/O3odKKk4 
Circle
Weightlifting Fairy Kim Bok Joo


They have no love triangles.
WFKBJ

Oh my Ghostess (kinda)

Bring it on Ghost


Goblin
The Gentlemen of Wolgyesu Tailor Shop
Fight For My Way 
Strong Women Do Bong Soon
My Shy Boss
Beautiful Gong Shim
Moorim School
Oh My Venus
Sassy Go Go
Weightlifting Fairy Kim Bok Joo
Suspicious Partner
Descendants of the Sun
Goblin
The Girl Who Sees Scents
Shopping King Louis
W-Two Worlds

Hope that helps
\ ^o^ /
can I add Kill Me Heal Me to the list?
Warm and Cozy and Bubblegum both have some love triangle but the guy worries about the female lead a lot
In time with you (tw drama), good guy but with love triangle
lucky romance
Sorry, love triangles are really a popular thing :( I dont like it very much though, I just live with it lol
Chicago Typewriter- The male lead wasn't the nicest to the female lead at first, but once he warmed up to her, which actually happened very quickly, he was always there for her and always thought about how his actions would affect her before doing them. I can't say that he never did anything wrong or that he was flawless as a person, but he tried to stay true to his morals to the very end by trying not to do anything bad. Even when he did make mistakes, he regretted it and tried to make up for it. You also can't help but like his character as it is very lovable and memorable. The only thing Chicago Typewriter has that doesn't match your request is that this drama does have a love triangle but, the second male lead never initiated anything with the main female lead, so frankly it's a very inconsequential love triangle.
Dramas where the main lead is good and lovable:

The Princess' Man
49 Days
Reply 1997
Romance
9 End 2 Outs
Witch's Romance
Queen In Hyun's Man

Hmm but all of them with love triangles :)