how do i tell him?

ok so me and my boyfriend ended up having sex one night when i was spending the night at his house we did use a condom but it broke and then we had sex maybe once or twice after that but he pulled out and according to my cycle i was ovulating the night we had sex so im going to wait til im able to take the test but im worried about his reaction is there anyone who can give me some advice on how to tell him and both our parents if i the test does come back positive im only 18 by the way