Why won’t he try to better himself?

I’ve been with this man for 7 years and it’s been great. For the last year I’ve been consistent in the gym and changing my lifestyle over all. I’ve felt bigger and not confident so I finally decided to do something about it. He’s under weight and needs to eat and go to the gym but he won’t do it. He says he will but doesn’t. He doesn’t keep up on hygiene and doesn’t actively communicate. Nothing is ever his fault. If it’s in traffic, or about food or how I’m feeling. Nothing is ever his fault. We’ve talked about this a million times but he doesn’t even attempt to change the way he talks to me or comes across. I’ve turned down lots of other men for him, gotten in shape for him and he can’t change for me. It’s not like what I’m asking for is ridiculous or selfish. It’s for the health of the relationship. What should I do. I love him but this is starting to become exhausting.
Updates
6 mo
I didn’t mean to sound full of my self or rude I just meant that we’ve been together for 7 years and men have approached me plenty of times throughout the years. Maybe that wasn’t the best thing to say to get my point across. I have worked on myself, my appearance and lifestyle and I just wish my partner would put in some work too. As we grow we change. I just want us to grow together.
Why won’t he try to better himself?
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