Sticky situation

My guy has a problem with one of my guy friends. Me and my friend have been friends for about a year now and we have stayed close. He was gonna take me prom but I told him not to and stopped talking to him as much when I started talking to my guy. My dude get aggravated when he texts me and I’ve told him that he really has nothing to worry about but it does mess with him and I don’t know how to cut off a close friendship like that. Tips? Advice?