Every time I open my heart to someone I care about, I end up being very disappointed. If you ever betrayed me, I don't know what I'd do.
--Lex Luthor, SV 6x21 "Prototype"
Lex says this to Lana and I suppose he could be speaking of Helen, his previous wife. She did betray him, true, but we haven't really had a mention of her since the third season—but Lex and Clark, forced by circumstance, discussed this very topic just two episodes before. So yes, Lex is comparing his relationship with his wife to the one he had with Clark.
Clark: Nothing's ever good enough for you, Lex.
Lex: The truth would have been.
--SV 6x19, "Nemesis"
Lex believes this, yes, but with the revelations of "Prototype", we see that the truth may very well not have been enough, that Lex might have betrayed Clark anyway. We learn that Project Ares is not new, but has been underway for three years. So would the truth have stalled Lex from his path as the self-proclaimed Protector of Humanity? Or would it have made the Project that much easier to complete? He's using alien DNA to augment human DNA for his soldiers, his "assets". And Clark's DNA, Clark's truth, may very well be that grail he seeks. He has plans in "procuring a replacement", he says here when the samples from Titan prove finite, which may echo his line to Lionel in "Justice" on how he's "protecting our investment". Could he have been protecting that investment when he rescued Clark from the tunnels?
This would be a sinister turn, yes, but even more sinister if he still cares for Clark. The humanity that he displayed in those tunnels isn't an act. But Lex is capable of doing terrible things to the people that he knows and loves, using their bodies without permission for protecting his emotional investment as he did with Lana by faking her pregnancy.
And what he's done to Lana, not only recently, but throughout their relationship is just setting up that relationship for failure. He manipulates, he plans, and expects love to be the result. He fabricates a child so that he can have real children later. He spends the same amount of time wooing Lana that he does on Project Ares. He wrests her away from Clark and blames Clark for turning away from him. In fact, he's done more to get these two together, by prying them apart, than he ever did when he played matchmaker.
Then who, exactly, is he disappointed with? These are tests that no one can pass. Does he really want blind devotion, loyalty to a fault, or does he want to prove Lionel right, that he is unlovable?
And he does subscribe to Lionel's brand of love. For Lex isn't unlovable, Lionel does love him. Lionel has rationalized murder, coercion, and electroshock therapy in the name of that love. To make Lex strong. And Lex is strong: strong enough to command resources and men, strong enough to make a resistance force for the growing number of metahumans and/or the alien invasion he's sure is coming.
But in order to make that resistance force, he has to change and warp the humanity that he claims to be protecting—so that they are no longer human but something else. They become what they've been chosen to fight.
These soldiers, this army, each one of them is as strong as Clark. Clark, who will later become a self-proclaimed Protector of Humanity as well, errs here. He ends up killing Wes Keenan because he exerts the same force as he does when he fights Kryptonians and other Zoners. He becomes, for a moment, the dangerous force that Lex believes him to be.
This is escalation. This is how Lex and Clark shape each other.
We have met the enemy and he is us.