Online dating is a load of bollocks. It's full of pervy, creepy, socially inadequate men who have fuck all chance of finding a woman in the real world hence they have to lurk online hoping to go on a date here & there. Then they realise what pathetic non-functioning losers they are, how incapable of any kind of relationship they are, and disappear.
A decent, normal man who had a pair of balls to call his own would man up and give a genuine reason. The sort of spineless twat who says 'Lets go on another date' arranges it and then cancels at last minutes/stops communicating etc, well they're pathetic and not worth thinking about. And I guarantee they will STILL be on the same dating site in months or years time, still incapable of a relationship with a real woman.
Frankly I couldn't give a fuck if people think I am whiny or needy because of the above, I'm not, it's simple good manners and courtesy. I wouldn't just stop communicating without a reason and I'd expect that in return.
OP, I'll give you some idea of the calibre of men out there. Hopefully this will make you feel if not better, then that you're not the only one struggling with it. I should add I am a bloody good catch and not one of these men if they'd come up to me in a pub would I have been likely to give the time of day to, let alone take me on a date. Having said that, they were very much the cream of the crop in online terms (which again gives some idea of the standard out there...)
My 4 most recent dates:
Man 1: Date went well, spent literally hours kissing after. Date 2 arranged there & then. He got ill & cancelled, kept texting me for the next couple of weeks whilst on his deathsick bed. Eventually texts petered out. he is still on there, and changed his profile the other day to complain about how he couldnt get a date 
Man 2: No attraction my side. Bit weird, borderline racist. Definitely no kissing. He text me after with a load of smut. I replied and said sorry, I didnt feel a spark (really nice, kind text). He replied and said 'dont worry it would only have been for sex' !
Man 3: pre date wanted me to think of him as my boyfriend
. Date 2 arranged before Date 1. During Date 1 said he didnt want me to leave, and stay til date 2 (arranged for 48 hours later). The next morning text me to say he wasn't ready for any kind of commitment...
Man 4: Date on Tues. Went well - similar to Man 1 above. 2nd date arranged for next week when he was back from hols. On Thurs I get a text telling me I'm a player for being online late at night, that's he's a one woman man & that I was bullshit 
None of my friends can believe this, and are even more incredulous when I tell them that my experience isnt even that unusual. There are a lot of mosconceptions about online dating, that it's a place where you're likely to find a life partner being the major one!