As for the protection thing...
Yes, Sam can hire protection, but as Clark pointed out, if they're not married for five years, there is no 'statute of limitations' on his paternity claim. Right now, there's an end date, if they don't stay married there isn't. If the end date didn't change, then maybe I could see him leaving, but not to leave Christopher - who he's coming to love very deeply - in paternity limbo until he's an adult.
As many of you have complained, Clark's been wrapped up in his own little world. Lois has startled him out of that. First, with telling him she was going to end the marriage and second, when she told him she's actually on medication. He's been reflecting [unseen] on what Martha said [we'll see some of that next time - as in 'I'd thought a lot about what Mom had said' or something to that effect - I thought it was in this part, but maybe not] and when Lois finally opened up to him, even if it was to tell him it was over, he finally started to realize that even though his life hasn't been great [in the sense of no Lana etc], hers hasn't been either, something that he'd been too busy wallowing to really think about. In fact, he's finally realizing that hers may have been worse in some ways - how bad must things have been for her for her to actually believe that the world would have been a better place without her, even if she never had contemplated suicide? [Believe me, I've been there, it's not a fun place.] It's snapped him out of it - at least that's how I see it...
As for the kiss... I didn't plan that - he just sort of did it...
Carol [who might be persuaded to post earlier tomorrow, but not Tuesday...]