dear integrate. ( I like your name ).
I used to be a classic jealous scorpio, and I would like to share what did the most to begin changing that for me. In the beginnin/"be discreet", and to be responsible about STI's. this was in highschool. Then came a day where I was at a party with one of my partners hangin' out on my lap, things were good, and I looked across the room to see that another partner was flirting with a person I knew was respectful. I had a moment of awe then, observing myself inwardly, realizing that I personally couldn't feel jealous when there's someone sweet actively being with me. This suggests my jealousy was based on insecurity entirely, because once I could tell I would be loved regardless of how well my other partner vibed with that other person, the feeling was completely gone.
That was at my intro level of maturity with poly, after awhile, I came to be genuinely happy for my lovers good times . (I was also getting laid as much as 4-6 times day. BTW, Taigarun's sex-positive advice is super legit, takes some practice, and lots of soul searchin'. long term benefits may take years to master, but then you'll be masterful, younger, more time for more quality love making). Switching between 3 lovers kept the sex really fresh, always new things, new combinations, and getting so much sex made lasting forever -pun intended- come naturally. -really it's a shame so many people suffer from premature orgasm, in a more poly environment sex became immeasurably better. -but to each their own I guess.
The next level of sexual maturity involved realizing what the grandfather of Non Violent Communication has to say about right and wrong being pathological constructs of hierarchical decree, shackling language that limits our ability to mediate and de-escalate our own troubles. Instead purely focus on what your needs and wants are, including meeting the needs and wants of your loved ones. (learn compassion for your enemies well enough, and you may well start finding ways around their cosmetic, egoic position as 'enemy', through identifying what needs their ultimately trying to fulfill, and you might just become a jedi/better a getting your needs met). the best link I've found on NVC, (changed my life forever, skip around the lecture series, it's kinda hokey, but it'll make sense within 5 minutes, I promise)
_____http://www.youtube.com/watch?v=W8-u3ecqI-Q&playnext=1&list=PL52B2657324EE800F
this one's for anyone opposed to corporations, Rosenberg speaks of 'slave language'
_____http://www.youtube.com/watch?v=YvFeY5GXtQo
Bottom line, your perceptive force, you, that comes from the very most center of your being. Hence 'centering oneself' generally involves forgetting about how you are seen, 'what you are', alla dat, it's nonsense. That which makes us feel 'good' about ourselves, each one is an internalized external identifying trait, constructing our ego. Let go of the need to be anything you aren't naturally. Let go of the idea noone's gonna leave you, you change every 7 years, so will 'they', it's actually borderline pathological to believe young adults are meant to be 'forever'. People grow and go where they need to be hopefully, just busy yourself about making your needs fulfilled, making your one life worth it, and the rest happens organically.
Easier said than done, I know very well; however this is a path, not a destination. We learn how the paths run and gradually transition from crawling to walking to running to flight, and at any point sharing honestly your experience can help both those with more and with less experience than you. So keep it honest, question everything, and trust more your observation of what's happening than what you still think is supposed to be happening. ***and by the way, I respect that you've come this far. you're actively trying to help yourself, which is the first step in you being able to help lots of others, namaste,