Well that's what being human is. People who can control their emotions and not act selfish are very rare indeed.
It's not about expecting anyone to control their emotions--it's expecting them to be somewhat considerate which is well within the range of "what being human is".
I may not be able to avoid jealous feelings but I can refrain from interfering with the other person's relationships. If I find myself making that mistake I take a step back and reflect rather than push heedlessly along. If I can't do that then I show exactly why I don't deserve to expect more from the relationship.
One of the most annoying things in the world is a sex friend who agreed to sex friend terms and then thoughtlessly decides on their own to push for more. *Annoying*. LOL I'm super biased against whatshisface for that reason.