I feel like jealousy is a broad term. They don't feel envious over material possessions because they thrive in community instead of indivuality. They do feel possessive though, moreso towards offspring than partners considering they're polygamous.
Possessiveness escalates in confined environments. Considering the ML's deep-seated connection to MC, he probably views him as a pod member hence why he's super overprotective and possessive.
This is just an interpretation tho (since scientists havent actually researched this topic) so plz take it with a grain of salt!!!!!
Source(s): https://headlines.peta.org/abducted-family-corkys-story-will-break-heart/
Darcy & Roy Press https://share.google/9k6YJbA1Wd8slr2oZ
https://ls.berkeley.edu/news/do-animals-get-jealous-people-researchers-say-it%E2%80%99s-complicated

Nerds, is it possible for orcas feel jealousy? I know they have high emotion intellectual or something but I thought they were like simple emotions (ex: sad, happy, mad). I was just curious as I was reading this and I can't get clear answer from google