Steadily in love male leads?~?

No abuse and no wavering from episode 1:

• I Need Romance 3
• I Hear Your Voice (there's a girl that likes the ML, but he never returns her feelings / there is a point where he forgets his feelings due to amnesia but it's brief)
• Sound of the Desert* (I wouldn't necessarily call it abuse, but he does pursue her aggressively - but she's strong and just sasses him back)

No abuse and no wavering once he falls for the FL but doesn't have feelings for her from before the drama starts / doesn't fall for the FL in the very first episode:

• Healer (he hides his identity / keeps his distance at first for fear of hurting her)
• Bromance**
• Love O2O*
• Love in the Moonlight (FL thinks he likes the second FL at one point, but she's mistaken)
• The Princess Wei Young*
• Live Up to Your Name
• School 2017
• The Eternal Love* (ML has concubines but does not see them)
• Witch's Romance
• You Who Came from the Stars
• Noble, My Love (there is jealousy and obsession; for dramaland its fairly benign, but some might consider it abuse)
• Strongest Deliveryman
• It's Okay, That's Love
• Weightlifting Fairy Kim Bok Joo (ML had a crush on the FL as a kid but doesn't recognize her right away, otherwise I'd put it in the "from episode 1" list / his ex shows up at one point but doesn't ever really pose any threat of swaying him as far as I can recall)
• Because This is My First Life (he figures out his feelings a bit late, and his ex shows up at one point but only confirms his feelings - no wavering on his part)
• Sassy Go Go
• Descendants of the Sun
• Queen In Hyun's Man

Dramas where the ML breaks up with the FL at some point, considers marrying someone else, or actually marries someone else for plot reasons, but only loves the FL / his heart never wavers:

• 1% of Something (they break up / ML considers the possibility marrying someone else because he doesn't think he can make the FL happy)
• Sungkyunkwan Scandal (ML runs away / plans to marry someone else because he doesn't know the FL is a girl / doesn't know she has feelings for him / doesn't want to drag her into a scandal)
• In Time With You** (ML is the FL's best friend and tries to date other people / tries not to love the FL for fear of losing her if they were to break up, but he fails and just ends up loving her more)
• Moon Lovers Scarlet Heart Ryeo (they end up marrying other people for plot reasons, but only love each other until death)
• A Love So Beautiful* (he's slow to figure out his feelings + shy about admitting them once he figures them out + they break up at one point, but he only ever has feelings for the FL)
• Pinocchio (ML and FL break up because the FL's grandfather / ML's adoptive father doesn't support the relationship... and they listen? He comes around, but that took away from the enjoyment of an otherwise super committed ML imo. His heart never wavers)
• Love Lost in Times (ML has to marry someone else for political reasons, but his heart never wavers)
• From Five to Nine*** (ML's grandmother tries to force him to marry someone else and I think he agrees at one point because of threats to the FL or the temple, but it's brief and his heart never wavers)

* Chinese dramas

** Taiwanese dramas

*** Japanese dramas

It's been a while since I watched some of these, so apologies if I missed any details.

 Marine:

What a comprehensive list, honestly, thank you so much! I've seen the majority of the titles listed, but of those I haven't, I really think I should give Sound Of The Desert another try, I always hear so many raves about the otp but I just didn't like the first few episodes/the female lead when I attempted a watch for the first time so I never even got far enough to see any romance. I'm also around ep 12ish of A Love So Beautiful (largely bc the Eng subs, last I checked, are only available until then) & I'll probably finish it, but he's slow as ffffffffff in reciprocating lmfao.

You're welcome! Committed head-over-heels and non-abusive male leads are my favourite, so those account for at least a third of my completed list ^^.

I also didn't love the FL in SotD right away, but she grew on me. I enjoyed the love triangle and the teasing, but the best part of the drama comes after she commits to her choice imo. 

Yes, he's maddeningly slow! All the ALSB episodes are subbed now. You can find links on the MDL page. Just scroll through the comments to find the right episode :) 

Love 020, he falls for her over video gaming and is just so gone.  It's awesome.  

Second boss and me

Second Beautiful Gong Shim, male lead is a favorite.  

Ok so maybe give falling for innocence a shot.  Doesn't love her at the very beginning but it's honestly fairly fast and he stays devoted.  

Go Ho's Starry Night...I'm gonna not say more cause of spoiler territory but ya know...it's actually awesome.

I hear your voice, He stays very steady, and it's a very very good drama.  

• The Greatest Love
• Fight for my way
• Shopping King Louis
• Healer
• While you were sleeping
• Live up to your name
• Moon Embracing the Sun
• Ruler: Master of the mask

https://mydramalist.com/15460-5-ji-kara-9-ji-made

https://mydramalist.com/22580-boku-unmei-no-hito-desu

https://mydramalist.com/16192-doctors

https://mydramalist.com/412-good-luck

https://mydramalist.com/15999-moon-lovers-scarlet-heart-ryeo

https://mydramalist.com/2985-hanazakari-no-kimitachi-e

https://mydramalist.com/288-49-days-2011

https://mydramalist.com/2905-kingyo-club

https://mydramalist.com/16973-love-in-the-moonlight