Fiancée holding a grudge for 2 years. Any way to fix it without being the bad guy?

We planned on getting married this year, but she’s picked at every single thing I’ve done since we met (3 years ago). We had an argument while we were in the midst of moving in together (me moving into her flat) and since she’s been extremely and unnecessarily critical of me. She told me that I’m an emotional black hole and that I’m not supportive of her, so I’ve tried harder to listen to her and be there for her. I’ve made an effort to listen more, to be more open, to be more supportive. None of it has helped. She’s still as critical and condescending as ever. I’ve tried being more assertive, and when I am, she says I’m being aggressive.<br><br>We live together, I pay 1/3 the bills, I help around the house. I cook and clean, we go out on dates, I show her I care, but this grudge she’s been holding and the way she talks to me is just awful. I’ve tried talking to her about it gently, passionately and even aggressively. Nothing has made any difference. She told me that when she’s upset she needs to get things off her chest, as bottle it up can lead to her being passive aggressive. But she never seems to be happy. Anytime anything happens it’s turned into a negative and she rants at me.<br><br>I don’t want to be in a relationship like this, but she’s the love of my life. I don’t think I’ll ever find anyone like her. I’ve already put the wedding on hold and told her it won’t happen while this is how things are. I feel like I’ve done everything I can. I’ve been patient, I’ve tried talking, I’ve tried being understanding, I’ve been giving. But nothing seems to help. Ever since we moved in together it’s been like this. If anything I’ve done to make her happy has ever mattered to her, she doesn’t let it show. Anytime I ask her what’s wrong she just says she’s stressed and depressed. Red flags or not, I don’t want to break up with her. Is there any way I can improve things without being the bad guy?<br><br>TL;DR: Fiancée critical and bringing up past while I try and be a better partner. How can I improve things without being the bad guy?