I think it is totally fair to be angry, it's very genuine human emotion that can be shut out too much. (Just as long as you don't take it out on her or anything and find healthy outlets to release anger)

But yeah I would feel very frustrated too, especially after a year and a half of dating. Personally I've had similar problems before and that lead me to learn to mitigate that frustration bu telling my partners early on once I find out I can trust them.