There’s many where the female starts to be this badass female lead but than she turns into a damsel in distress.
but have you seen
The legend of Fu Yao? (she was very bad ass but that went down hill. She meets the male lead and always gets beat up so he can save her.)
Also do you mean he is a weak like no fighting skills at all?
Also mentally in Untouched Lovers the lead girl in both parts of the drama she is very strong girl but not in the physical aspect but she doesn’t let no one step all over her, and the male lead is the one who is very manageable. Like he believes people lies and stuff like that.