Should i be worried about my boyfriend?

So my bf is friends with this skank. She was into him and told him so before we even got together. And she's always trying to get him to go over to her house and trying to get him to talk to her and help her with stuff. But he always reures me that he adores me and only wants me. And i really feel like he's different from most guys. We had a huge fight about it tonight, and he promised me he'll never do anything with her. But should i be worried??? I've been cheated on before by other guys.