"You are only ever yours"

What does this quote mean? Or, rather, what do you interpret this quote to mean? Serious question.

You can never belong to anyone else only to yourself despite what you may believe at any particular time. 

The only person you can trust to be looking out for best interests is you.

Thanks 

 

This is a bit J17, but I had a falling out with my partner, and rather than engaging with me in conversation, she's instead electing to post random messages on her Twitter. The above was one of them.

your partner has essentially said that she can only trust herself. She must have been hurt badly, it seems. 

The answer to this is obvious.  Or it would have been on Oldrof.