Yes, I think I basically agree with you. That is, I think he has to have had some dreams about a settled life, but I don't think he's necessarily had that dream (certainly not in a recurring way).

When I saw DALDoM the first time, I didn't even really question his assertion. I didn't think he'd spent much conscious dreaming about Lisa in particular, or even Ben, nor did I think he was really all that angst-ridden about the family-fantasies at all. But more significantly, I think that what prompted that particular scene was his self-consciousness at having Sam there. He was so worried about what Sam might see that his subconscious started conjuring up things that he wouldn't want Sam to see.

Like trying not to think of a white elephant.

But clearly, I'm in the minority.