Dead end relationship?

I have been engaged to my fiancé for 2 years. He has told me he hasn't been happy in the relationship lately. I asked him why ? He said he doesn't know. I asked what his ideal partener is. He says he doesnt have an idea for ideal partner. I asked him how can I fix the problem , if I don't know what it is? He says he doesnt want to break up. I told him I could tell he has been losing interest. I have been making more of an effort lately. Trying new recipes, new hairstyle , new date night ideas. He shuts down date nights. Makes no comment on my hair or food .sits on couch looks at phone . I told him I don't know what to do , feels like nothing is good enough. He replied " I deserve to be with some who appreciates me". Yet... he doesnt want to break up. What should I do?