[He wants to hug her back immediately. Truly, he does. But he can't... he has to be sure. He hates the doubt that her worries have manifested in him, and before he commits to anything else or lets himself be distracted or comforted, he wants to understand- to help her understand. He can't just sweep all of this under the rug and pretend this is fine.]

Is... is that how you really feel, though? [About me. About us.] Do you believe I'd be happier with someone else? [His hands clench at his side, unclench, half-lift to touch her before dropping down again. He can't, he can't.] You said it for a reason. How long have you been worrying about this?

[Did he cause this? Did his moping, or his failure to communicate his indecision, develop this fear in her, or did it only bring what already existed into the light? It's possible that this whole time, either she didn't say anything or he missed whatever subtle signs she'd been giving him... neither option is good. He sure as hell doesn't feel like he did nothing wrong.]