Forgive me, I've been following Ripley on and off (I don't like Clark/Lex pairing up with other guys; it's me, not you) but I did see the part where Lex thinks Clark's attraction to him might just be biological.

So why is Lex saying no? Maybe he does think Clark's attraction might be only biological (insecurity), or is he mad at Clark for (insert reason here), is he afraid that if they DO get back together, something will happen and Clark will leave again?

And frankly, is Clark trying hard enough? Have him channel his inner Kal for the sexy, turn on the charm, the puppy dog eyes, have him get down on his knees and pour his heart out how much he wants Lex. Do you really think Lex can remain firm (heh) in the face of abject Clark begging? Nah!