How do you get rid of a friend?

my friend who shall remain nameless because i do log onto fluther at his house…idk if he checks but i will assume he does….well hes a DICK.

hes in my ‘crew’ which consits of me and three other people [him included] and hes a dick to all of us, theres many examples but one being… he flirts with my ex when i clearly tell him i still like her a lot….i feel betrayed when you do it….can you please stop. WHAT SHOULD I DO..