He's probably not married or in another committed relationship, but he probably is keeping "on the line" as a second or third choice, hoping another match that he likes better will either come along or get more interested in him.

I held out hope for way too long recently that a girl who didn't want to meet after seven weeks in OC was "just shy." Eventually, I pressed her on it ... first she said she was too busy to meet, then was too afraid of trusting too fast for safety reasons, then finally said something like, "It's hard to know how to proceed when you're communicating with a lot of matches at once, all of whom have different qualities, and it's hard to even tell what you want then ..." Which I viewed as finally admitting, "I'll only meet you if eventually some of these others don't turn out well after I've met them."

Not that there's anything wrong with communicating with other matches and meeting multiple people, in the early stages -- it's just you ought to be at least "tied" for a match's interest, if he/she is truly potentially interested ... not a distant second, third, or fourth, etc.