Please recommend romance dramas where the ML is willing to take extreme risks or make extreme sacrifices (even the ultimate sacrifice) to protect the FL. 

Dramas like The Princess Wei Young, The Legends, Mr. Sunshine, The Blue Whisper, Love Between Fairy and Devil and Crash Landing on You.

Love is sweet : At the beginning ml creates problems for fl but after he always supports & protect fl

What you asked for is actually how I would describe this drama in a few words: Love and Redemption

If you like this trope, you'll love this :)

Thank you for the recs lanzhanya, sweetdreams, Gauri and Dejes ^^

 lanzhanya:
Who Rules The World

Just watched this and it definitely fits!