Curious to your opinions.
Yes and no. Single just means not married. If they've had relationships, or been a "player" but not attached or have an enormous porn and lubricant collection then they could be HL. If they've lived a solitary, hermit-like existence possibly with cats....(just kidding about the cats) I'd be strongly suspecting LL.
Probably those who had never had a long-term relationship would be suspect from the LL perspective, while those who had might be nursing their wounds and mainly interested in a good time rather than anything more significant.
My prenup would be rather long - or maybe not - keep it going, or I'm off.
If she gave sex to either
I think it is a bad sign, but not necessarily a sign of LL.
When you see it coming, duck!
I'm kidding really - the only point would be to smoke out the dissemblers.
It is so tough to smoke out the dissemblers. My DH told me up front that his ex-wife "pushed him away" and that he never wanted to be in that situation again. Of course at this time, we were NOT living together full-time (I stayed with him 3 nights a week) and we were at it hot and heavy. He was good at it, he was very giving, he was strong and confident, I couldn't imagine why anyone would ever push him away and said as much.
Years later after his every-single-day-without-fail pushing, and his constant criticism of my skills in EVERY department (not just sex) his bizarre schedule and my naturally lowered level of interest due to things not being new, taking antidepressants to keep me sane while being in school and working and raising his kids and taking care of his needs while having mine mostly ignored, not to mention his over the top buttheadedness when things sexual did not go his way I understood EXACTLY why she pushed him away.
Of course that's not saying that would happen to everybody, I am just saying that at the beginning when things seem all good, you can't imagine how far they can change. I didn't know I'd become a LL. I wouldn't have ever guessed it at the beginning. Of course I had no idea that anytime I said I didn't want sex would count as him being "pushed away"
In your semi-open arrangement, I still don't get why hubby gets his gender of choice and you don't.
Fair would be either you both get your gender of choice or gender is a non-issue... fully open in other words.