need some help with my friend..?

I cant handle it anymore...

She decides she likes a certain boy.. and then thats it the blinkers are on.

Because she has feelings for this particular boy she seems to feel that they are now her property and if she sees him flirt or show affection for some other girl she goes mental and on a ***** tirade..

She will eventually try it on and they wont be interested but then she will moon over him and talk about him non-stop to everyone. especially me.

I've had enough. We have been the best of friends for about 22 years straight from preschool to now.

I know its kinda rotten to say this but she is DESPERATE for a boyfriend and Im pretty sure that boys can smell it on her.

she gets herself so emotionally involved with a boy who has no idea about it and when they say something mildly mean she goes crying to me about it.

BUT IM SICK OF IT!

Please could someone advise me how to deal with this. How to let her know gently that she needs to shut the F*ck up and find someone that will treat her right and move on..lol

thank you