I hardly ever have time to do anything other than read this forum (hence my minimal amount of posts in so much time), this thread got me out of my lurking.
Violette, I am in pretty much the same situation. I'm not 40, I'm 33, but what's the real difference anyway? I'm not here to offer platitudes, because I know they ring meaningless and false, and I'm not here to comfort you because I know you don't need that. I just want to share a few things as a person who is living a similar reality to yours.
Since high school, I've been overweight, lost 60 pounds, and have been fit ever since. I've dressed like a bum because I was self conscious about my body, and I've dressed amazingly when I haven't been. I've done all the things you've mentioned- tried to examine, alter, experiment, see if there's anything that made a difference. And I've come to learn that all the things you listed- age, beauty, weight, etc... absolutely none of it was/is as much of a determining factor as living. And I mean real, uninhibited living. Chasing your dreams, being passionate about something, letting yourself feel and show and share the emotions that living life brings... THOSE are the things that make you live life the way it's meant to live.
And ya know what, that is the ONLY thing that's ever made a difference in terms of connection and value to others (and myself). I hate to be annoying and speculate and suggest WHY it is that you & I are in the position we are, but I truly think it's because we have such a hard time letting ourselves live. Of course you don't want to give yourself the permission to go out there and ride the rollercoaster when you feel so undesirable, stunted, unwanted, and not special. But that's WHY we feel this way, because we've built some sort of system of stipulations regarding when living life is "allowed." It's always allowed. And it's always necessary. It's a vicious cycle... you don't want to do it because you feel like you don't have those things, therefore no reason to celebrate and experience and be happy. But not letting yourself be like that... that's what keeps other human beings away. I know you probably have no reason to believe me or listen to me because, after all, I've always been single. But the moment that dawned on me, I looked back, I examined, I altered, and the theory proved itself. And continues to.
There's so much more to life than being with a man/married/kids/etc. And until you let yourself go out there and experience and enjoy it all with no limits, that man/husband/life won't come. It's kind of a happy thing to realize imo.. that "indulging" your own personal happiness leads to what's evaded me for so long.
The previous comment about "a wall of NO" is so on target. Just say yes to every little thing that might make you happy, and the rest will come. No resistance, no spite, just that kind of 'anything is possible' and "i'm open to it" attitude that comes with youth (which we still have).
Ok, enough from me. Just want you (and me) to be happy.