I don't think your question is anything to do with age really. A lot of people feel hypocritical about balance when they open long term marriages just as much as people starting their relationship life. What you are concerned about is very common.
At some point I would think its a matter of choice at your age/stage and then perhaps switching it up at some point. I think there is something to be said for monogamy and poly in terms of experience. Its really not so much about one or many loves its about how competent you are with communication, giving space, being independant rather than codependent, having common goals and values, that sort of things that make a great relationship(s).
So you could go either way I think, commit entirely to your boyfriend or agree to the possibility of being committed to many people. Both experiences are valid and worth experiencing, the point would be to chose one or the other and not have one doing one thing and another doing another.
I would suggest giving it more time. Time has a way of making these choices more clear. There will be lots of opportunities, I would think, to be with many people, as long as you keep your integrity, be honest, respectful, considerate and caring, really I think you have many chances at love, either monogamously or not.
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