If I were a cynical person, I'd say it's probably because another woman has entered his life, and he no longer needs you "in the stable," as the assholes say.

But I'm not a cynical person; I'm a hilarious person. So I'll say because he's been made part of a secret government task force consisting of himself, a bio-engineered half-shrimp half-man, and the haunted remains of Yul Brenner (they're haunted by Sammy Davis, Jr.). Can you BELIEVE I don't have a TV deal yet?

Four years is a long time. Maybe he needs to separate from you in order to feel like his life can move forward. Maybe he kept talking to you out of a sense of obligation, and that's worn off. Maybe he lost his phone in a computer explosion that destroyed his mailbox.

Whatever the reason--be it romantic or depressing or otherwise--it's an exes' right to stop calling you. Any human being is allowed to say they no longer want to date any other human being, and then decide whether to schedule a lunch date the following week or leave the country.

Trying to read too much into the actions of someone with whom you've ended a long relationship is like rooting through the hypodermic disposal bin at a hospital: what you're trying to find may have once been helpful to someone, but now it just causes sharp, stabbing pain and an elevated risk of H1N1.