Don't be jealous.
While it's hard to not be jealous at all, it is possible to control that jealousy. Sometimes a bit of jealousy can be a good thing (depending on the way it's interpreted). Jealousy can be a sign that your significant other cares about you, for example, he gets jealous when you go out for lunch with a close guy friend. But, a lot of the time, jealousy will get you into hot water. When you get too jealous your partner will start questioning your trust in him/her. And the last thing you want is for your partner to question your trust.
Although it's hard, you have to learn to control that green-eyed monster so that it doesn't start ruining your relationship. Try to focus on the positive and trust your partner's actions and decisions.
Another issue is being jealous of your partner. Luckily for me, I rarely get that feeling (which is great because I'm naturally a competitive person). While a bit of competition can be healthy, being jealous of your partner really hinders your relationship because you're never truly happy for his/her achievements. You'll always want to be better or have more than your partner and that will result in a toxic relationship. So like I said before, stay focused on the positives, try to be happy for each other's achievements. As a couple, share victories and loses.
Have a great Friday!