Moving out

My boyfriend and I have been living with his mom for nearly a year now. We now have an opportunity to move out on our own. The problem is, he's very messy. I do most if not all of the cleaning myself, and it never stays clean for long. I'm kind of afraid that he will bring it with us when we move and have thought about just living separately. We've talked about it before and he claims that he doesn't care because this isn't his house, but that when we move he'd take more pride in cleaning. How can I believe him? Should I just live on my own for a while?

UPDATE: My boyfriend and I moved.... And things changed! I have to fuss every now and then, but he does a great job of helping me clean up and cleaning up when I'm gone. I'm so proud of him