I have a friend whom we will call Ken. Ken and I are friends since the first semester of university. We're pretty close and we are part of a friend group where everyone is quiet close. We've been friends for nearly 8 years. We've graduated, all of us are working and we still meet up every month although everyone lives in different parts of the city. Now, I'm not very comfortable with physical touch, specially I hate when anyone touches my hair ( I have waist length hair) and I told everyone that. Ken loves to touch hair, I have repeatedly told him that I dislike it, I find it uncomfortable. He still touches the ends of my hair thinking I wouldn't know. Yesterday, all of us met in the restaurant and he was touching the end of my ponytail, I shot him a look he stopped but then he did that again. So, I just made a bun. It may sound like nothing but I feel like my personal space and opinion isn't being respected. After returning home I'm reconsidering my friendship with Ken? if I cause a fall out will that make me an asshole?

P.S. I haven't said anything yesterday because I think that'll cause a tear in the friend group, also I think Ken has a crush on me. Which I've guessed for a while so in several occasions I've made sure to point out that he's only a friend.