And to a lesser extent, this.
Make sure she's on the same page as you when it comes to monogamy. Jealousy is natural, but don't let it get the better of you. Until you have evidence that she's cheating or will cheat on you (e.g., you find her fucking some random dude in your bed, or she tells you that she's not into monogamy), then there's no reason to worry, and letting yourself worry to excess will only hurt your relationship. If such evidence ever arises, you will be fully justified in dropping her ass. Like 6 said, if she really wants those kinds of experiences, then she's not the kind of girl for you. If it comes to that, your only rational decision will be to leave her and find somebody else.
But this is all hypothetical. You have no such evidence yet, so just chill. There's no reason to get worked up about it; you have nothing to worry about right now. Just make sure you two are on the same page, enjoy what you have, and don't let your paranoia get the better of you.