The SML in ashes of love does bad things qnd goes all evil to get the FL. I WANT THAT KIND OF SECOND LEAD IN A XIANXIAN DRAMA. 

Summer Desire- Sml is not Angst but he is possessive

Destiny of White Snake 

Love and Redemption 

Not a Xianxian, but a Historical. SML is Obsessed with the FL in 'Mr Sunshine'.

Just here to say GURL IT HURTS why would you do that to yourselves xD... 

 yarnie:

Just here to say GURL IT HURTS why would you do that to yourselves xD... 

Haha, I just love this psycho second lead trope, even though it hurts :D

 Spring Flower:

Haha, I just love this psycho second lead trope, even though it hurts :D

well fair enough xD I also have some plots I like and prefer even though it hurts reading/watching it! 

Not exactly what you're looking for, but maybe worth checking out:

  • Love Between Fairy and Devil - Xianxia. One of the main villains "does bad things and goes all evil" in order to resurrect the woman who saved him (not the FL) because he's in love with / obsessed with her.
  • The Legends - Xianxia. A stoic and "pure" secondary male character feels attracted to the FL. He can't have that, so he purges those feelings. Those purged feelings get mixed with something (the FL's blood iirc) to make a SML who is a little trouble maker (but not really all that evil) with a lot of the FL's character traits and he's attracted to / a bit obsessed with the FL.
  • The Princess Wei Young - Historical but not xianxia or wuxia. The villainous SML becomes obsessed with the FL and does bad / evil things to get what he wants: the throne and the FL.
  • The King's Woman - Wuxia. The ML is basically the villainous SML. He does plenty of bad / evil things to get what he wants, including poisoning the FL's fiance and blackmailing the FL into being his captive. Although the ML and FL are together for a good portion of the drama, it doesn't end well for them