Can a guy exsplain this to me why ?

Ok so im a 28 ur old women my female next door neighbor and I are very close from hanging out there a few times I've been around her 21 yr old nephew I never looked at him in a way other then a friend since I've never dated younger men at all the thought never crossed my mind so anyways we ended up some how chatting online very innocently one day and he flirted I was hesitant to flirt back after a couple of times chatting he told me his number and asked to text him so I did like 3 weeks later once while bored he texted back once then never again so one night while drinking together he started to open up alot ( he's very shy and had sex with only one girl before) he was telling me he's noticed me since I moved in the building how beautiful I am an how much he liked me an wanted to get to know me better asked me all kinds of questions of my likes and dislikes so anyway we ended up kissing for a good hour making out but nothing more then kissing though besides holding hands he asked if we could hang out again next weekend I said yes he never called again an completely ignores me when we see eachother since then Its been 6 months I've moved on since ( he hasn't had sex or dated anyone since our kiss ) but I can't help wonder what happened ? At least the dudes my age you know when there not interested or the reason for the rejection cheating usually ect. but I just don't get what happened here lol can any dudes explain ? Is it as simple as he wasnt into me an the complements were all bs ? I mean he didn't get *** so what was it for? Lol idk clueless ..... I did like him so I would like to know thanks : )