First, my sympathies, OP... What an undesirable situation... I'm hoping you can get through to him, and it's all just a big misunderstanding... I hope I don't sound too negative below, and please don't be discouraged, I'm just going to give my honest opinion, as the kind of guy I am...
>>11 Sorry, but as a guy, in a healthy relationship, as well as several bad ones with clingy psychos, I've got to say in this case, that it's just unacceptable what he's doing... That "needing space" excuse is soooo overused, it's the guy equivalent of a woman saying "I'm just too into my career right now" to get away from a guy she's not into... Most (and I only say most, because there are exceptions) guys who say "I need my space" need to be told to "drop the metaphysical fancy-phrases, and just get over yourself"... Now, again, I say most, as there are some truly psycho women out there (I've dated two of them), who you do need space from, as much as possible! (I'm no longer dating them, of course)
Even if he's got nothing to "talk" about (and we guys aren't usually ones to talk a lot), the fact that he hasn't called to at all to check on you & see how you're doing is, in my opinion, generally unacceptable, let alone the fact that he's (again, just in my opinion), ignoring phone calls & facebook messages asking if he's ok or even still alive...
There's only so far an excuse like "I've been too busy to turn on my phone or check e-mail or facebook lately" can go... It's just not believable in this day & age that someone goes over a week without access to a computer or their voice mail, and can't spare even a measly five minutes to call you back, after you tried to call him?! When a relationship is supposedly a committed one, it's not a convenience or luxury, you're supposed to be there for the other person, and in your case, you're just wanting to ask how he's doing or what he's been up to, standard chit chat, and his lack of any response isn't even giving you the reassurance that he's even alive out there...
In any case, the bottom line is that though I don't know too much about your specific case, I still think it's unacceptable, no matter how much "space" he may need, to drop off the face of the earth, not even returning a call or message for over a week now.... He needs to have that made clear, and he's going to have to gain some maturity, and now, and start treating the relationship as a serious one, rather than a play time, or luxury, to be enjoyed only when it's convenient for him...
Again, sorry to be so harsh, I just really dislike guys who neglect their girlfriends, having dated several girls who were used to man-bashing due to them having previously dated guys who neglected them in that way...