Advice about breaking up please

My boyfriend is always too busy. He never tells me he misses me, never asks to hang, rarely texts me (we used to talk all the time), and usually gives me one word answers when we do text. I don't know what to do. I've tried talking to him about it and every time he says he's busy. About a month ago he started volunteering at the fire department and that's all he wants to do. He goes there about 3-4 times a week and the other days he always has an excuse for why he can't hang. I've tried explaining to him that if he wants to see me he'd make time no matter what but he just said he wants to see me but I need to understand that he's busy right now. He's been "busy" for almost a month now. I'm so fed up. At this point I feel like breaking up is the only option left. I'm so upset. I miss him and want to be with him and I don't understand why he doesn't seem to feel the same way. Should I break up with him over a text, call, or in person? Advice please! I would really appreciate it.