https://abcnews.go.com/Health/MindMoodResourceCenter/man-par...
It would just make you attracted to a different group of people. That wouldn't be chaotic at all.
Quite simply, change happens.
This is not a bad thing. Change happens all the time. You can't be scared of it, or try to stop it, because it is inevitable. You can only embrace it.
But also, somewhat more rationally, taking a pill is a choice. Not everyone would take it, and certainly not enough people to significantly impact society in any way.
More people wind up with lovers that are their friends and/or equals instead of an object to be doted on.
But in all reality, people aren't going to simply stop pursuing people and you assume that a pill is going to reverse attraction instead of enhancing it. Bi- and pan-sexual are actual things. I know this from personal experience, and I didn't need a pill to figure this out. By your logic, though, I guess I'd be attracted to... no one?