It's definitely implied, but not stated outright. However, the cues (inherited from classical Hollywood) are pretty obvious. I voted "They very well might have done," but should have gone for the "of course they did" choice."
What isn't so obvious is why Saavik decides to stay on Vulcan in STAR TREK IV: THE VOYAGE HOME. Is she pregnant with his child, as early script drafts indicated? It's left up in the air, but it's definitely possible.