Ive seen this term a few times, but never an explanation. As a person that (mostly) associates themselves with being Bi, ive never experienced any sort of “cycle”. Its it just an internet injoke (cause it sounds like bicycle).
Admitting that sexuality is mostly based on physical attraction tends to get judged as shallow, but it’s true for most people, me included. That doesn’t mean personality, values and shared experiences don’t play a role. I wouldn’t abandon someone for something out of their control like aging or illness, but knowingly changing their appearance for the worse with overeating, bad hygiene or ugly cosmetic surgeries would be a dealbreaker. And I wouldn’t stick around with a hot person with a shitty personality.