I don't see why there can't be more than one reason. For instance, jealousy caused by fear and insecurity.
Then the question becomes, what exactly are you afraid of? What's making you feel insecure?
Me: 31F, straight
Seamus: My husband, 32M, straight
Dragon: My boyfriend, 29M, pansexual, married to Fox
Fox: My boyfriend, 29M, homoflexible, married to Dragon