You started this whole thing with "So I am about to lose it here and really don't know what to do."
If you have told her repeatedly and she has not changed in the slightest, I'm not sure why you think she will change in the future. Unless you really haven't expressed how big of a deal it is (and I don't mean implied it, or hinted at it, i mean directly stated its a big deal) then I don't see what you're going to do differently to change her mind. She's an adult, you can't force her to do anything. For the sake of complete clarity, what i mean when I say "express how big of a deal it is" i mean you sit down with her and say "dear, this is literally driving me crazy and if it doesn't stop, I don't know if this relationship is going to keep working." If that doesn't change her behavior, nothing will, and then you either decide to deal with it or you don't.
In summary, if the situation is about to cause you to lose it, and you've already tried to motivate her to change her behavior by telling her how important it is to you, and you cannot change her behavior because she's an adult, then it seems like your choices are:
1) lose it
or
2) stop being in the situation that's causing you to lose it.
It seems you don't want 1, which is why people are suggesting 2. What are your other options?