Should I tell him

I have this guy friend that really likes me, he’s been tryn to get wit me for 2 years. He’s a good friend, a nice person to talk to, but he’s not my type. He keeps asking me why I don’t like him, all I say is I don’t know. I don’t wanna tell him because it may come out really rudely, and I don’t want to be rude. He has anger issues and if we dated we would get into arguements all the time, but since we dont date, I dont have to deal wit it. I dated his best friend, even thought he wouldnt mind, im not going to go wit my ex’s best friend(plus I still like him, and he says he likes me lol). and he is really ugly, I cant even picture being wit him without getn disgusted. Should I tell him this? I don’t want to lose him as a friend, but it seems like I already am because im not telln him why I dont like him.