What needs are not going met that need offset? So far I'm only getting "not happy when he's off with other lovers because I don't have another lover for me." You say you are envious -- so you wish you had what he had. Another lover. I don't know if this would help you on jealousy...
What are pros/cons to monoamory (desire and ability to love one at a time) and polyamory (desire and ability to love several at one time) to you?
What are pros / cons to monogamy (closed and/or married to one partner) and polygamy (closed and/or married to several partners) to you?
I mean, if it ends up that you are monoamorous and give being in a polyship a try in the dating world and then discovered that it is not for you after all?
That's ok to feel. Perfectly valid. You are allowed to try something and decide you don't care for it.
I guess I'm just confused still. Like... if this doesn't work for you -- can't we end this polyship? And then you go date others then? Find the monoship you seek that will feed you better so you can thrive?