You know, I really see myself in you, -Ever-. The minute things are a little off in my relationship, I go straight to sexual jealousy. It's silly, because it wouldn't make the tiniest bit of sense in our (fairly unique) relationship for her to "cheat on me". But that's always the first place I go.
Did she say there's another guy? Did she say she's done with you or going to use you as an "emotional crutch", whatever that means? No. She's said:
<ul><li>She's stressed about her career.</li><li>She wants time with her girl friends</li><li>She wants space from you.</li></ul>
There are lots of things you can conclude from that, but notice that all the stuff about "other guys" has happened in your head. There's no evidence out there in REALITY to support that conclusion.
I'm also not saying that's NOT happening. What I'm saying is, you've got yourself crazy here because you're making up Reasons for Why This is Happening. That's always a losing game, in terms of your own sanity. You have no idea why this is happening, really. None whatsoever. And aren't you a little interested in finding out what's really going on?
The way we human beings work is, something happens to us (Girl X cheats on us), we come to a conclusion about the Way Things Are ("You just can't trust women, they'll cheat and use you."), and then we bring that conclusion to every relationship for ever more (You're on the lookout for Girl Y to cheat on you). You'll see that conclusion everywhere, even when it's not there. That's the past, of course, and it's long over, unless your mind latchs onto it and imposes it on the present and future.
Again I'm not saying I know what she's up to. I'm just saying that what you posted and what you're dealing with here isn't in any way her fault (or yours, really)--it's just the feverish churning of a worked-up imagination. It doesn't have anything to do with objective, real reality. I suspect you already know that, on some level.
All that said (whew) I'll join the communication bandwagon. Thing is, you can't demand communication from her. That never works. You've got to be in communication with her first--let her know about how bad your mind is working overtime here, and what that's like for you. Not like blaming her or dumping it on her, but being responsible for where you've gone with this. You watch, your honesty will draw out her honesty.