Hi
Gee, I'm trying to think of something hopeful to say.
It sounds to me she is being honest with you. In a nutshell, wherever she is planning to go with her life right now, you don't seem to fit those plans. Maybe nobody can, she just needs time to build her life herself.
And regarding the sex?..has there not been enough of late?.is there a level of dissatisfaction from her?..that is a big one.
This is tricky because you two are living together. I don't see much that you can do. Just don't pressure her and let her have that independance if she wants. Give her space to work out how much she cares about you.
Don't follow her...there are warning signs here and she is either ready to move on from you, or is disillusioned. Hopefully for your sake it is the latter, but this will only mend if you let her work it out for herself.
Sorry I couldn't say anything more positive