how do i break up with my boyfriend at university?

i have been with my boyfriend for 3 and a half years. we have gone through so much together but i feel like i cant stay with him anymore. Last year he dumped me because he felt he wanted the single life at college but then we got back together. i am now having second thoughts of getting back with him. we cant talk as much and in the last 2 weeks our longest talk has been under 10 minutes. im only 20 and i feel like i want to move on with my life but i dont know how im supposed to end it without really hurting him or even how to do it. i dont want to do it over the phone and if i go to his uni i wont be able to let myself hurt him. what do it do ??