I doubt that they are perfect. One becomes blind to faults initially.
At 17 you don't need to be exclusive to one, but you should be clear that you don't intend exclusivity until you are older. Since you have a six month relationship with the existing boyfriend I suspect he considers it exclusive. You need to make a decision and be honest. Either stick with the relationship you have, or break that off and try out a new one, or ensure your existing boyfriend knows you intend going out with others too and have both (if possible) as fun only.
Thing to ask yourself first is whether your existing relationship is no longer what you really want. After all you invested time in it, you want to know whether it is worth risking or slinging. But at 17 you have plenty of time to experiment.