My long-term girlfriend (19F) and I (19F) (both our firsts) want to take a break to sleep with other people and see what's out there

My girlfriend and I are both 19 and have been together for almost three years. We’re each other’s first relationship and first everything. Our relationship is genuinely very healthy, we communicate well, trust each other, don’t fight much, and we’re both really happy. I know it sounds cliché, but we truly see a long-term future together.

Recently, we’ve been talking about the idea of taking a break, not because anything is wrong, but specifically so we can casually date or sleep with other people. It’s not that either of us strongly wants to be with other people right now, it’s more about the fear that, later in life, one or both of us might feel resentment or “what if” feelings about only ever being with one person.

The idea is that we’d take some time apart, explore a bit, and then come back together having a better sense of ourselves and what we want. We’re both on the same page about this being the reason for the break, and neither of us is doing it reluctantly.

That said, I’m nervous. I’m worried that even if we agree to this logically, it could still cause jealousy, insecurity, or emotional damage that we don’t fully anticipate. I’m also worried about whether a break like this actually strengthens a relationship or quietly ends it.

Has anyone been in a similar situation (especially young couples who were each other’s firsts)? Did taking a break to explore actually help, or did it change things in ways you didn’t expect? Any advice or perspectives would be appreciated.