A reason for this is their holistic engagement -- they want time to register what's happening.
To sum up the Virgo man in a single word, it would be "practical." He sees things as they are, with no sugar coating.
Likewise, he tends to prefer the company of others who are similarly reserved. But once he's truly smitten, he's in it for the long haul.
This doesn't mean that Virgo can't form strong attachments. Once the Virgo male has committed to a relationship, he is forever loving, patient and supportive.
Don't ask too many personal questions, or you'll likely get an inscrutable face in return. If he's still finding his footing, he's resistant to really involved romantic entanglements.
This guy needs space, to find some sense of being "clear" and able to make the best choices.