I simply don't understand that if you want the guy to "commit", that you go out with someone who "wants to keep it casual"? It doesn't take "months" to figure it out, you can probably do it on the first couple of dates. If a guy tells you he wants to keep it "casual", it is because he his telling you the truth and you better be happy with keeping it that way. So, yes, I would blame yourself for sticking with a guy for months or years who already told you he won't commit. Know what you really want and stick with that.