Do I have the right to be angry about this?

Ok, so when my boyfriend and I first got together about a year ago, I had a few issues with my best friend and him flirting. I brought this up nicely and he reassured me that he didn't like her like that and apologised etc. Fast forward to about a month ago, and I got really angry one night when he decided to go out for the evening (when i invited him out that night he said no, then I got ill and couldn't go and he decided to go) and said something stupid about him and my best friend. He hung up and the next day we sorted it out. However, around a week ago, we were all out together and my best friend got really drunk and started crying asking if I really though him and her were flirting etc. I hadn't said anything about it to her, so i knew it had come from him. When I confronted him about it, his justification was "Well you kept having a go at me about it and never said anything to her, so i thought I'd say something to her to try and clear it all up". And since then he point-blank refuses to speak about it. Am I right to be angry?