You don't get jealous if you're dating someone for the right reasons. If you date someone because of any of the following reasons, you may get jealous:
-she's hot
-you want people to think you're cool by having a gf
-she makes you feel better about your insecurities
-she's wealthy or powerful
-she fucks well
-she prevents you from feeling lonely
-you depend on her to fix your problems or you try to fix her problems and play the hero
All of these things will lead to jealous behavior because you being with her is contingent on doing these things or providing these experiences for you. In other words, you are being needy. When she does these things for other people, you feel threatened or marginalized because your relationship is built on shallow or superficial pursuits. That feeling of being threatened or marginalized is what comprises the jealousy. You want to "possess" the person to give you these shallow things.
However, if you date someone for the right reasons, then you are unlikely to ever feel any jealousy (or at least, any significant jealousy that you couldn't easily dismiss). The right reasons are:
-you communicate well
-you treat each other with genuine with respect
-she makes you a stronger individual by helping you improve yourself (in other words, she doesn't do it for you)
-you admire the choices she makes
-you want her to be her best possible self as an individual
-you have similar values about important life issues
When you love someone for these reasons, you may get sad if things end, but you don't take it as a personal threat and wouldn't feel marginalized if they'd be happier with someone else. Instead, you'd encourage them to do what is best for them. You'd respect their choices. And you'd love them unconditionally, even if that meant saying goodbye.
Good relationships are all about bringing out the best in each individual through teamwork. They're not about forming unhealthy dependencies and losing your identity in a series of pleasurable interactions.
