Can't seem to keep a man. No problem getting them--just keeping them. They generally fly off after 4-6 months

You don't mention specifics, so I would start by asking you to consider these two questions:

1 - What kind of men are you attracting?
2 - Are you driving them away?

For both, you need to take a good look at yourself and try to understand if this is a "problem" on your end. Inventory yourself and see what you can come up with.

Maybe your only attratcing guys that want fun, and not anything long term?
Maybe you have some personality quirk that the men you've met so far can't stand.

And of course, it could simply be that you just haven't met "the right guy" yet... and you need more time and experience.
:)

Are you being to clingy?

I went through a phase kind of like that when I was in my 20s and it was not till I reached the late 20s and got a full life, became very independent , and was very happy alone that I met a good guy.
Take things slow when you meet a guy, very sloww, be confident , positive and be very busy, don't be available to him all the time(this was generally the mistake I made in my younger days and spent too much time with them) , don't rush into intimacy too fast(this is generally the problem.. get a guy emotioanlly attracted to you first), get to really know them, ask them what they want, listen to them...

cant seem to keep a man. No problem getting them--just keeping them. they generally fly off after 4-6 months

What could be going on between meeting them, and them leaving? How often has this happened? A little more info would help.