Advice please.

Okay so I believe my fiancé got jealous because I called my best friend which is a girl "boo." Then he was like I understand if that's how y'all talk but I thought I was the only one u call boo and which he got upset with me about it n I told him in the past that's how we talk to each other all the time and which he knows that. So I want advice for if I was in the wrong for calling my best friend that? And what I should do about the situation?