The landlord at my mom's new apartment is really nice, and my boyfriend's mad at me bc of it?

Okay my parents recently separated, mom met the landlord at work and they started talking and she found out he had an apartment open. So after a few weeks of knowing him, she started to trust him enough to move into one of his apartments.(It's one big house with three apartments) He's really friendly and nice to us, and he helped us move in and fix up the apartment. He and my mom talk a lot and he invited us to breakfast this morning at his mother's house. We went and when I told my boyfriend he got mad at me. He says the guy's a "child molester"? Does he have a right to be mad at me?? What should I tell him?