What To Do...

Alrighty folks, so my best friend is a man. We have been friends for a very long time and we do a lot of stuff together. We travel together, we try new things together, he is genuinely my best friend. My fiance understands that and has no issue, he doesn't control who my friends are. But recently, my best friend has gotten a girlfriend (totally crazy btw whomst the fucc would date that guy) and she is not happy with me AT ALL. She refers to me as "The blonde girl on your phone" and gets super jealous of me. My best friend and I have never had romantic feelings for each other, I was actually convinced he was gay! I'm tired of people assuming that I'm having an affair because my best friend is a guy. Neither of us are just going to stop being friends because our partners disagree, we have been through too much. What do I do?