First Breakup Advice?

I am 18 and my (ex) boyfriend is 17, and we had a very strong and loving relationship that survived long-distance for almost a year and a half. Just a few weeks ago, he said he needed to take a break because he felt that he was changing as a person and didn't feel the same spark we used to have.  There is no anger or hard feelings between us, and he really wants to stay friends, but I am absolutely crushed. How do you attempt to stay friends with someone you're still in love with? And how do you recover from having your heart broken by the person you love for the very first time? I feel like I've lost my best friend and a part of myself. Any sage advice would be greatly appreciated ❤️