Scott wasn't used to actually having to say what he was thinking, or feeling. Usually Emma, or Jean would just read his thoughts because he was thinking so loudly. Dating you was different, because you couldn't hear his thoughts. Your mutation wasn't telepathy, and you couldn't get into his head like Emma or Jean would. That didn't stop him from trying. Sometimes he would simply stare at you, completely silent as he thought of all those things he could never force himself to say out loud.
When you asked what was wrong he simple shook his head, muttering something under his breath before returning to his staring. His expression was so tense you thought something had to be wrong. Still, he didn't speak, just stared at you in a way that felt like he was trying to share his thoughts with you but failing.