Inspired by this thread. I’m (unscientifically) testing a hypothesis here: Most men (straight and gay) will prefer the first option, women the second.
Twenty spunks is more than ten, no matter how ya slice it.
Sex with a woman is often much better after a few practice sessions. You have to consider that, too.
Female here…I’m going for 20 with one partner rather than a boatload of one-night-stands. Practice makes perfect, you know! 
Do I get to keep one of the ten?
Else, I must agree with RickJay.
One partner 20 times. Sex is great, love is better, both together is amazing.
As far as I can tell from the OP, you can keep 'em all. but you only get to have sex with 'em the once.
I’m a man with RickJay, too. There’s a simple arithmetic to sex; the more the better.
One partner 20 times.
Male, non-religious but monogamous.
Can I get four of them, five times each? Or two or three at one time?
Can I get slaw with that instead of fries?
I’m male and I agree with Ruby, actually. I’ll be very frank here and say that I’m a crummy lay the first time and a sensational one the tenth time. To go for the “10 x 1” option rather than the “1 x 20” would be denying the girl (and me) the best I have to offer.
Straight male here that would prefer 1 partner 20 times…I’m going to need at least a week and a half though.
I’m going to continue to bust your hypothesis. I’m male, and I’d go for one partner, 20 times.
We don’t have to do it all in one night, do we? Cuz then I might choose the former option.
Nice simulpost, dead0man.
“Once a king, always a king, but once a night is enough.”
Ditto.
Depends entirely on the women. Ideally the former but if the ten women I get to have sex with once are exceptional or the one I’d have sex with twenty times is unremarkable, then the latter.
Female here. Twenty times with one, definitely, and I even have someone in mind. Mmmm.
I will have to go with OneCentStamp and say that the first couple of times with a new person, I definitely am not at my best. I can recall only one lover with whom the first time and the last time were equally terrific, and that was a miracle of chemistry that I do not expect again.
Are you sure you might not have gotten that backwards? You seem to be declaring a preference for infrequent, unremarkable sex.
I like the way you think. 
BrainGlutton
Another male destroying your hypothesis - I’ll take 1 woman 20 times.
Perhaps this is oversimplifying, but a guy thinks “Sex 20 times or sex 10 times?” Yes, it’s just that simple.
1 person, 20 times.
If I’m only going to sleep with 10 guys once, either they’re really disappointing meaning I’d never want to sleep with them again, or I’d have my heart broken 10 times when circumstances keep us from ever sleeping together again. Right? That’s too much angst.
I’ve been involved in a few group gropes, never w/ ten people though. It was interesting, but certainly not emotionally satisfying. I take one woman ten times.