Dating a sociopath/narcissist (part I)

Question from a reader:

hey, i've been reading your site and i was wondering if you could give me your opinion on my ex.

a few months ago a guy who i had a fling with in high school contacted me and we got together(this was after two years of not seeing each other. [when we were in high school] we messed around(big mistake on my part) and he kind of stopped talking to me(which is to be expected.) somehow he got the idea i told his cousin what happened and he started a mission to destroy me, at which point i got prank calls for hours on end telling me i was ugly, etc. praying on my insecurities. anyway he left high school and i guess got in trouble for beating up some guy who was bullying his nephew, and he moved to texas.

i didn't talk to him for two years, but i added him on myspace recently cuz i wanted to let go of the past etc. he had just moved back here(he lives with his male best friend) and he drove two hours down to where i live to see me. that day we messed around again and he asked me out. i declined because, well, i knew his past and i was kind of freaked out by him. he was COMPLETELY different.. he was showering me with compliments, he opened up to me, we had the best time... lol, he even started crying because i asked him about his grandfather that had died a while ago(he had told me two years earlier about it and how it had effected him.) he even says at one point he wants to marry me. this is all in the first week. anyway, as they say, the honeymoon phase doesn't last forever.

well, for one thing he askes me for money all the time. and three weeks into the relationship [i have to pick him up drunk, he doesn't call back for a few days] so i break up with him. he says nothing. later that week [i contact him online] and he calls me and askes me whats going on, saying he didn't get my texts(he uses his friends phone) and he loves me and hes so sorry. we make plans to hang out the following week.

on the way [to some excursion] he sees some kid getting beat up by two older kids and flips the car around and confronts them. they say they're siblings and just playing, so we leave, at which point i give him a big kiss because he was being a hero lol. anyway, he says he wants to get something to eat so i said okay, you're driving. [he drives two towns over and] i started crying because i knew he was going to leave me there and he gets out of the car and says he'll be right back. 20 mins later and he doesn't come back.. leaving me in the middle of a strange town without my glasses or a license in the middle of the night. he doesn't call me the following week or apologize or anything, so i write him a letter breaking up with him and havent talked to him since.

obviously this guy isn't the one for me, but do you think he's a sociopath? the reason i ask is because he seems to have no qualms about abandoning me somewhere or taking money from me, or just all around being manipulative and a liar. however, he has shown some empathy -- ie, where he stood up for that kid getting beaten up, and he's had to grow up in a very hard environment which could have made him extremely anti social and manipulative, but maybe not a true sociopath. what do you think?