13 week lab thinks bf is a chew toy

Hi all! I have a 13 week old lab. Had her since she was 8 weeks. She is teething so she is a little bitey. The thing is, she has stopped biting me a bunch. She will get mouthy with me very rarely but for some reason she is very bitey with my boyfriend. She accidentally got her tooth in his ear and he pulled her off him and it ripped his ear open. I’m thinking it’s how he responds to the biting. He moves quickly, tries to get his hand away or move her away, which I’m thinking she thinks is a game. Typically I ignore the biting or say ow and she stops. I’m just not sure why she really goes after him lol. Advice maybe??