Most Helpful Guy
Ask yourself this question: are you okay with him having sex with other girls on this "break"? Because that's the purpose of it. Don't kid yourself about that.
If you aren't okay with that, then this is a breakUP, which is exactly what the vast majority of "breaks" actually are.
You guys have been together for quite a long time considering it was your first serious relationship. It's the NORM for such relationships not to last forever. By what he's been saying, he's wanting his chance to go wild and experience life and bang a bunch of girls. That's what most guys do during their college years. He's realizing that the clock on that is about to run out, and he doesn't want to miss his chance. Once school is over and he has to start working, party time is largely over: he'll be working long hours and have very little control over his life for the first few years of his career.
I know this isn't what you want to hear, but you need a reality check. If he wants this now, it's likely going to continue to be an issue until he gets it out of his system, and it's going to be something that gets between the two of you until then, assuming you are together.
I always tell people "there is no such thing as a break; you either stay in the relationship and work on the issues TOGETHER, or you break up." The thing about relationships is: what YOU want doesn't matter if the other person wants something different. Relationships only work when people want the SAME thing in the relationship, and you can't change someone else's mind, you can only change your own.
I hear a lot of "but I don't WANT that" or "that's not what *I* want" from people with relationship problems, and part of what they aren't accepting is that, unlike most parts of life, being in a relationship isn't about what ONE person wants, it's what the TEAM wants, and teams only work if they have the same goals. A "team" with opposing goals isn't a team, it's a mess that will quickly fragment and explode from the tension.
The other important thing to understand is that you have to determine what the other person wants from the very beginning, BEFORE you get together with them and invest too many emotions in them, because once you're together, it's too late. You aren't going to change, and neither are they. That's why it's so critical not to choose partners ONLY on attraction, but ALSO on compatibility, because if you don't, your relationship doesn't have a long-term future.