@kokuto
"If it was just about getting A Nian's help, then why would he admit he wanted to kill her beloved CX?"
To gain her trust, maybe, since A Nian knew XL tried to kill CX before. I mean denying this fact would have made him look even more suspicious,IMO. What other reason do you believe he had? If what you are saying is that beside getting A Nian to help him, he was also truthful, than I am not disagreeing.
"Okay, so you are saying that XL is lying to A Nian, and that he really intended to kill XY from the start"
No, I am not saying that. To clarify, I don't believe XL went to look for XY with the intention of killing her, I believe that at that point he was open and willing to hear an explaination from her, the turning point for him was her refusal to air kiss him underwater. As I said before, I believe he misinterpreted her reaction as a confirmation of his doubts. So when they were back on the surface I believe he was prepared to either kill her, either kill the bugs, but he had a change of heart because he realised XY was telling him the truth.
"Much like the question of XL's lethal intention in this chapter, I find this contradictory and confusing."
Than I guess it's up to you to find a better explaination for this part " Xiang Liu’s sharp finger retracted in that moment and Xiao Yao never knew how close she was to death.", beause that's the best I could do, honestly.
There's plenty of ways he could have learned more about the Lovers Bugs.
Yes, but that doesn't prove he learned more about the bugs down the road, he could have done his homework from the get go. The drama clearly showed he was interested in how to have them removed from the start. Either way, I believe that he was determined to find a way sooner or later. I definetely believe he accepted the bug with the intention and confidence that he will be able to come up with a solution eventually.