This is not a movie. It's your real life. So let's not pretend it is, well, pretend.
I will say right now that dating for five years at your stage of life, unless you're engaged, is generally a lousy idea. We see these folks all the time, male and female, who sewed up their early dating lives with one person and then, ten or twenty or thirty years later, decide they'd missed out.
Time to put on the big girl panties as they say, and tell this guy that you want a break. Be prepared for him to protest. Tell him you both need a chance to see what else is out there.
Give it a timetable, say, six months.
During that six months, date whomever you wish, and that means have sex if you want to (please engage in safer sex practices). Do not see your boyfriend during that time. Keep communications to a minimum but they don't have to be utterly shut off.
Determine whether you really missed him, per se, or just the security of having a steady boyfriend. You may find it's the latter more than the former.
Oh, and be prepared for even the discussion to end things. He may want to skip the break and move on straight to breaking up. So be it, if that is what happens.