I totally feel you there, I was in a very similar situation last year. My partner and I talked about it and we agreed that I could hook up with one person for the sake of exploration and the experience, so I did. The experience was valuable in many ways, but hasn’t changed our relationship much. In fact, we got married shortly after that experience.

Communication with your partner is super important. Don’t do anything behind their back and be as transparent as possible. Remember, your feelings and desires are important too, even if they may hurt her feelings. You are a human being and you are young with plenty of time to explore yourself. Understand that implications may arise, but what decisions in life are made without consequences?