I hope no one has mentioned this before, but I can't help but think about how Jeph said that QC had only spanned about 6 months in story time (maybe pushing 9 months by now?).
My point? Well, usually it takes longer than that for a couple to decide to get married. And since the Dora/Marten relationship only started a little while ago in the greater scheme of things, they have a long way to go before they decide to do it. (Not to mention that neither one of them seems to even desire marriage to anyone until further notice)
So, it'd be a huge commitment for Jeph to develop this relationship long enough to lead to something like that. And would it be worth it? It'd take awhile to know for sure, and by awhile I mean at least a year in real time, if not two or more. I expect there will be more drama before that, of the relationship-ending kind, even, although I have enough confidence in Jeph to expect that it won't end up looking like a season of Friends. (in this case, I mean a breakup and subsequent hookups with the sole purpose of convincing the reader that the two "always loved eachother"

)