Have you ever considered simply asking him what's going on, and what changed all of a sudden?

Don't jump to conclusions. Slow down. Talk to him about it first so you can find out what made him stop talking as much. Maybe he's been busy lately, or he really is losing interest. Either way, you need to know what's on his mind before you decide what to do about it.
Remember that if communication is slipping, it can be strengthened if both people in the relationships want to put in an effort. Breaking up doesn't have to be the answer.

talk first!
that's the first step that i could suggest you to do
and i guess you can take another step after hear what he say... maybe there are some reason why he changed so sudden

Well you can talk first.. but by the looks of it id say prepare for the worst.

Hello:)

That's no good that he doesn't say I love you (I assume that's what you're talking about), but that's no reason to lose hope in the relationship. Try not to jump to conclusions, it just sounds like you're having communication problems. If I was in your shoes, the first thing I would do is talk to the person and try to understand what's going on. Like Laura said, breaking up isn't always the answer. If you really care about him I'm sure you can make it work.

Let him know your fears, and ask him what the problem is. Worse case scenario is he is losing interest, but that can be overcome by finding new ways to spice up the relationship. Anything from going new places to just taking up new hobbies together could put the spark back in things. But like I said, a little talking goes a long way, and that's what I'd definitely recommend.