Sims, by default, have always been aromantic - but willing to explore - and pansexual. This has not changed with the update. The update simply codified it in a way that the player could see and, more importantly, influence outside of gameplay.
Now, I don't have HSY yet, and I've only been playing with a dedicated married couple and their kids, but none of the premades have made a move on them, nor have they expressed much interest in making a move on the other sims. There was one want to flirt with another sim (who matched the played sim's orientation in my head) but the only woohoo wants I've seen have been "try for baby" with each other. (they have three. I'm done even if they're not. Yes, one of the two is family oriented.)
