I haven't had much time lately to comment on stories, but I have kept up with this one and would like to post a few general comments.
First, while the thought of Lois getting pregnant would normally revolt me, I find it an interesting plot development. I don't particularly want to read much after the baby is born because that would devolve into the mother and child dynamic which I don't think Lois Lane is suited for.
That said, I think that your Lois is frustratingly in character under the given scenario. You find you want to shake her sometimes as her emotions and feelings waffle back and forth over what she's doing and why. Her motives are clear and pure, but continues to fight against seeing herself develop a deeper, more romantic relationship with Clark. She still doesn't believe that such things really exist, so for her a strong enduring friendship is the best relationship that one could hope for. But while she trys to explain that to Clark I'm not sure who she's trying to convince, him, or herself.
Clark is Clark. Always the butthead. He may be the noble, self-sacrificing hero of millions, but he still clings to his parocial, and somewhat selfish, view of things. Just because his 'marriage' and possible 'family' aren't something out of a Norman Rockwell painting he can't let go of his self-pity over it. He realizes, and appreciates, what Lois is doing for him, but because it isn't the perfect 'dream life' he's always envisioned he has to continually spoil the moment with his bouts of pouting. Get over it, Man! What? He rather die because he can only have Lois' everlasting support and friendship, instead of sex with her?
Clark's feelings, while understandable in his longing and frustration, are not particularly sympathetic. His belief that he probably won't live anyway has darkened his emotions and affected his actions. The characteristic patience that would normally allow him to 'take what he can get' and hope for more later isn't there, and unless he reins in those bouts of self-pity he might just lose the 'half full glass' that he's being offered.
Of course, that is if the story contiues along the path that it has without any changes in a certain character's emotional involvement. Somehow I think things might evolve somewhat as the time goes by... but I'm just guessing.
Tank (who really hopes that Bernie comes up with a deus ex machina cure so Lois doesn't have to ruin her life by getting pregnant and having a <shudder> child)