I like that Lois has figured it out and is on her own with time to process the information. Usually in fics, Clark tells her and she immediately has to react - often badly, because her instinct is to retreat and emotionally protect herself. Here, she has time to work through the issues on her own terms. Sure, she's concluded (for now) that she can only be his friend, but she's not currently staring at his ass.
Once she gets another look and realizes that she could grab a handful of it if she'd only let herself, I'm confident she'll change her mind.