I don't think Lois is being unreasonable at all.
In her mind, there is no possiblity that Clark is in love with her.

Even after Lana said what she did, she wasn't willing to open herself up to the possiblity. It would hurt too much if she was wrong. So she simply assumed Lana was reading him wrong.

And from her standpoint, she is giving Clark what she believes he ulitimately REALLY wants: his freedom and his sons.
Sheiah has stated several times that she doesn't think Lois is in love with Clark in the "selfless, biblical" sense. I think this is an excellent example that she does.
Even though it is going to rip her heart apart, she's willing to give him up. She isn't going to make it harder for him by begging him to stay or guilting him in to it. And her sons as well, if necessary. To make Clark happy.

Now from Clark's standpoint, IS that what he really wants, or does he feel like he's being forced out?
I don't know.
On one hand, I can definitely still see some evidence of "double-edged guilt" when he was talking to his parents. That makes sense, since they were the ones who were pressuring him to love her in the first place. (I know that's not the way they see it Carol, but that's the way I see it, and I think that's the way Clark sees it, too.)
On the Other Hand, smile I wonder if Clark is REALLY ready to give Lois up. Of course he isn't, but I mean, does he realize how much it would hurt him and not just Lois and the boys?

I still wonder about shock thearpy. Is this enough? Or do we need Trask to attack Lois because she "seems to be close to the alien"? I don't know.