Argument with my sister

So is been 3 weeks that i havent been around my sister shes the oldest.. We used to hang around alot shes engaged to this guy she been with for 5 months, he seemed ok at first. My sister called me today asking how im doing and why i havent gone to her house like ive always done and i told her i dont feel comfortable around her fiance.. She asked why and i told her because i dont like the way he looks at me. She threw a fit and started talking nonsense defending him she wouldnt let me even finish what i was saying! The thruth is her fiance flirts with me makes me feel uncomfortable.. He winks at me when my sister is not around or looking. And i dont think he is a good man for her if his doing all of this to me. I mean shes not going to believe anything that i have to say this guy is just disgusting she dont even know his family yet and they are getting married so soon! Is ridiculous and alarming to me