I think their relationship makes sense mainly because of what happens to Vulcan, and by proxy Spock. While he's not the last of his kind, it does offer some implied hope for a future of Vulcans... as well as integrating with other species as a means of survival of Vulcans and their culture.
Also, it tied in perfectly with the exchange between Spock and his father, who indeed went through the exact same event and feelings in his life -- which is 100% backed up by canon. We just never saw Sarek and Amanda making out on Vulcan like that.
If anything, Sarek's comment illustrates that it WILL be possible for Spock to reconcile his love AND his logic and tend to both parts of his life. Dad did it.
It must have been nice to be Zach Quinto on set, is all I can say!