And these two never really *talk* y'know. I can see the goodbye as Jack telling him he's got to go, Daniel saying he's going to Atlantis then. Both of then nodding, fast and furious sex and then they'd go about their way.

I think daniel's too used to not having any permanence in his life to complain and Jack probably figured this was the best for both of them, since daniel wanted to go to Atlantis and Jack couldn't deal with not being with him all the time anymore.