Boyfriend advice

I'm 20 years old and I've been dating my current boyfriend for 3.5 years. He is and has always been my dream man and I wouldn't want to lose him but at the same time I'm feeling antsy and like I want to experience other people while I'm young and still figuring myself out. I don't think we could do an open relationship, but I don't want to break up with him and I also want to see other people (and him!)