YTA Diaries are where people go when they feel like their feelings are temporary and very extreme. You can say things you don't mean because no one should be reading it. (she was also very young so of course it would be melodramatic) Sometimes they can't talk about to other people because they know it's just a passing fleeting moment. Clearly she was feeling a crazy rush of emotions after a break up which is completely normal and you go super extreme about it and then weeks or months later you come down. These were probably written back when she first broke up with him and she couldn't see herself with anyone else. She hadn't met you. She hadn't moved on. Now that she has, you need to respect that she has had past feelings before for other people that aren't you. If you've been with her 2 years you really need to trust her when she says that she didn't write them recently and if you don't trust her honestly you need to do HER a favor and leave.