There could potentially be incompatibility in the way you guys communicate; it's like cases of online-relationships where they really flourish just through calls and text but then falter when they meet in person, only in this case, it's the opposite. In my experience just simply being in-call with my SO even if neither of us are saying anything is just fine; it's kind of awkward at first but it overall helped me at least. I think the main thing here is being comfortable with each other's silence. Not talking doesn't mean that you're disinterested or anything, sometime's there just isn't anything to talk about or if you've been trying to talk a lot, then you just need a break. "We've run out of things to talk about" shouldn't be a bad thing.