a) I have never been on OKCupid.
b) I have only read the first few replies to this post, so somebody might have written something like the following in the meantime. But:
Can't you put - right at the beginning of your profile?: "I am polyamorous. I am NOT a swinger. I am not INTERESTED in swinging. If you don't know the difference, do NOT contact me. I would rather send you a pic of my left big toe than of my tits, so anyone looking for a quick wank, just leave me alone! I am interested in the possibility of a serious relationship. If you are not mature enough for that, I don't want to hear from you. I will block anybody who doesn't respect my choices."
You might still get contacted by die-hard, hard-on idiots (block them), and you might scare off a few potential poly types (those scared by strong women), but I understand that there are enough poly people on OKCupid who will understand EXACTLY where you're coming from... and appreciate the no-bullshit approach.
You might throw in: "More interested in love [or "romance"] than in sex, though romance WITH sex is best option."
Because you've never been on OKC, I find it understandable that you might suggest something like this, but I don't think it's a good idea.
One big issue with online dating sites and profiles (and really the whole thing) is when people get frustrated with it, and then project the frustrated vibe into profiles and/or messages. I am bisexual so when I was on OKC, I was looking at both men and women. Frustrated men will describe the kind of woman they do NOT want to meet.
"If your pics were taken 10 years and 50+ pounds ago, don't message me"
"Tired of the friend zone, if you aren't ready for a real <man/relationship/whatever> then don't message me."
etc.
And women putting up the warning signs in the profile...that's the first contact, that's like you walk up to a lady and smile and say hello, and she immediately screams "ARE YOU AN ASSHOLE? I'M NOT HERE TO MEET ASSHOLES! I WILL NOT SHOW YOU MY TITS!!" like out of nowhere. It's...hostile.
EDIT: Point is, if trying to meet men or women, as a man or a woman, the last thing you want to do is convince them that you now completely dislike and mistrust the opposite gender because your experience has taught you they're just a bunch of awful people. It's like accusing someone of bad stuff before you've even met them. Not so nice.
And so many women have front-loaded the profile with either disclaimers, or descriptions of the kind of men they would rather NOT hear from...those kinds of things become a pattern, you see it enough times and you're like, ah. She's doing that thing. *sigh*
Once I noticed how many women do this, I had to really edit my own profile, as it was a bit disclaimer heavy. We often feel like we have to confess all of our flaws up front to make sure a guy "knows what he's getting into" with us, apparently.
My favorite profiles were funny or clever or both. There is a man who now works at my work (weird coincidence) and even though he fell into a "too young for me" category, I HAD to talk to him, because his profile was so cool. It was long. Like a million miles long. It took me an hour to read it. But it was HILARIOUS. I wish I were still on OKC so I could try to find and link it here. I like little inside references, too, quotes and such, to books, films, etc.
Be careful about repetitive phrasing. It makes your writing boring and bland.
I love....., I'm a total..........
I love........and plan to .............
I love ........... etc
You really LOVE all of that? Mix up the sentence structure and switch out some repeated words. And try to avoid a few words that too many ladies use, a couple that I can think of: "fake" and "drama." Also anything about "playing games"...much as we might want to say something about that, it's overdone. Instead of saying that you are honest and avoid fake friends, maybe say something like,
"You can count on me to let you know where you stand. I am a real cards-on-the-table kind of woman, and I won't leave you wondering what I'm thinking or what I mean. So at the risk of being a bit forward here, if you need the sort of date who will have you playing Mystery Dinner Theater at every stage, then I might not be the one. I prefer to be classy and tactful, without being coy.
But don't get me wrong, classy and tactful doesn't mean I'm afraid to get my hands dirty, and you'll find me some days with flour, or paint, garden dirt or motor oil, right up to my elbows."
Not all of that applies. But that is HOW I would write this kind of stuff. I'd convey the fact that I can do many hats, or paint a little picture of what life with me might be like.
As for what you are looking for, you want to try and describe the wonder that is polyamory.
"I am a married lady looking for a paramour, an adventuring companion, a lover and a friend. I am absolutely not a cheater or a swinger. I am polyamorous, which means that my wonderful, supportive husband will know all about us, and you'll never be a dirty secret. It also means that a deep, awesome, loving relationship is on the menu, not just a fling. Don't expect to put the sex cart before the relationship horse here, guys, just because this gal is already hitched. But if you've got the patience, the ride through this pretty country might just be worth your time."
I would not personally use that wording (because I'm not into the country thing) but I'm illustrating use of fun language to get a point across. Of course I think it's a fact of OKC that some men will always hope they can proposition you for sex or whatever, and you've just got to filter through those.
I don't think it's bad to allude to the possibility, but carefully done in such a way as to state that he's going to have to put in the time and effort to gain your trust first.