I need help figuring how to break up with a guy I've been seeing a little over a month. He's very nice and treats me very well, which makes things harder.

He's been introducing me to all his friends a colleagues, talks about meeting each other's parents and is planning trips for us two months from now, so I know he thinks this is something serious that's headed long-term.

I don't want to embarrass him or crush him - what's the best way to tell him I'm just not into it? There isn't anything specific about him, just a general overall feeling of "This isn't the guy for me." Can I get away with doing it over the phone? We haven't slept together . . .