There's a very fine line between being "the fun one" and being "the crazy one." My guess is that you consider yourself the first thing and the guys you've been with consider you that second thing. And men don't ever marry that second thing.
I'm not asking you to change who you are, but I am asking you to assess who you are. Because things you think make you fun might give guys the impression that you're not "long-term material." So I'm going to put a list out there. If you do these things, there's a very good chance that guys will want to hook up with you and then immediately decide that you should never meet his parents.
The Mystery Man's Signs That You Think You're Fun But Guys Think You're Crazy
-You dance on tables at the bar, even if no one else is dancing on tables.
-You frequently retweet Kim Kardashian in the hopes that she will mention you.
-You are wearing more than two belts right now.
-You start conversations with new acquaintances with phrases like "So what's your deal?"
-You are holding a Solo cup in 50% of your Facebook photos.
-You have uttered the sentence "I quit bartending to focus more on Tattoo School, but I quit because fuck school."
-You don't have a problem peeing in public.
-You loudly shout whatever shot you're about to shoot ("Jäger, bitchesssssss!!!!")
If you're doing these things, you can't be surprised if men want you for one night or one week but never any more. When it comes to being marriage material, there needs to be a little bit of boring thrown into the mix - normal bedtimes, having a good job, no online screaming fights. Because "boring," by your definition, means stability. And even the most wild and crazy guys want (and need) some kind of stability and classiness in their future wives.
Don't change who you are. But do try to change your expectations about what men want.