@Sprottenham hahaha I am glad you thought so!
I obviously don't completely understand it, but the numbers are from Master Controller, in the intermediate section. the number on the left is male and female on the right, most all sims start as 0/0 neutral so you can guide your sims to whichever gender preference, or just watch what they decide.
As the sim goes about flirting and acting and agreeing to flirts and kissing etc. the numbers change. If a Sim has a negative number, they will Usually not respond or will back away from advances of that gender. So you could make a monk type sim with both numbers in the negative.
So the firefighters Teddy(neutral) and Adan (bi) should really have hit it off with each other and with Alfie (bi) at the time. But sims will choose, yea or nay.
Adan(bi) is very enthusiastic about Vlad(hetro) and cheers when ever he sees him and starts to approach him, but Vlad just walks away.
Vlad (hetro) should have been all over Anya, but chose the trampoline. lol
Cherie could have chosen any or all of the firemen, but only chose Alfie.
Teddy (neutral) and Adan (bi) never chose each other.
Alfie got hearts for the females in the family but not the males. He got the hearts for Anya but Cherie prevented it going further.
I don't know who started it when he was with Adan just heard the woohoo sound. I think he started it with Teddy then after woohoo, walked away, didn't linger or talk, just zoomed to the computer.
And the interesting part is the numbers didn't change for Teddy! why? the male side should have gone up by 2, and the female side down. Do the sims have control of the number?
The choosing and avoidance is very interesting to me. so even when you hope to make it happen, (Me creating Adan) you never know. I thought it would be nice to have at least one gay or bi couple in the town.
But apparently, if there exists a sim like Anya then your whole town will become hetro anyway! :D