I've been lurking for a while and waned to respond to this. I sent my guy a message in October. We are not friends on Facebook. It said "sent" for months. It was only in December that he accepted the message request. He had read it when I sent it, but didn't want me to know. The thing about Facebook messenger is it will not say "read" until the person chooses to respond or accept the message.

I wouldn't stress it. Worst case is it's sitting in him message request folder and he hasn't opened it. Best case is he saw it and is chewing on how to respond.