Ex problems? Help badly I need HELP!?

Well in January I broke up with a boy that I had been going out with for 1 1/2 years because since his friend moved he changed so I left him on the 14 and my best guys friend asked me out we have known each other for like 2 1/2 years now and that was on the 20th well my ex his buddy that moved and I with my boyfriend were at this place together and left naggin my ex and his bud to come and after like 5 min of walkin they came up well about a month later i heard that my ex and his bud pulled a knife out and were going to kill my ex I am terrified and I need help what do I do with my ex and also I really think my ex is hott he is the best at basket ball and soo hott and how do i stay away from him. Best awnser get 10 points and 10 stars