Why do Libra men come on strong and then disappear?

I chat with this libra man online a while back I am a gemini woman he sent me some of the most wonderful emails and he told me how interested he was and that he only had his son and mom and now he has me. But he stopped emailing me What happen? The chemistry was there. I can't stop thinking about him. I look at his picture wishing for the best. What should a gemini girl do?