Air signs generally aren't the commitment type, so if you take someone at face value you might take a libra's flirting of need for harmony personally. Not all librans are the same, but they are shameless flirts and don't tend to like to tie themselves down. Do you know anything else like birthday/year/day? If so you there are plenty of sites where you can do a bit more indepth compatability for free.
Off the top of my head astrology.com has some free romance guides under their love section that don't need a birth time, and http://www.lunarliving.org/moon/moonmatch.shtml
you can do a moon sign match. Both of those will probably give you a little more insight into his character rather than libra generalizations