I can see that you love this man, but the question is are you both compatible? You clearly have a glaring value conflict--you're neat and he's casual--to say the least--when it comes to orderliness.
Such differences are hard to get around. You took off from his house because you couldn't stand the mess and because you hated the area in which he lives. Now you have asked him to move to your area.
I suspect that you have asked him to move to your area (and perhaps in with you) because you are laboring under the unspoken fantasy that life would be better for you both if he were to live in your tidy place. The reality is that your values will clash, no matter where he lives. Your house is clean now, but it won't remain this way with him in it, not unless you hire round the clock cleaning help and/or become his maid/slave.
Your problems extend beyond a value conflict. You also have to contend with his putting work ahead of his relationship with you. When you lived with him, his busy schedule prevented him from ordering his environment, which he had promised to do, but never found the time to fulfill.
Now you are asking him to move near you, and he says, once again, that work prevents him from doing so. Work always seems to stand between you and him. The issue here is who and/or what he places first in his life.
Time isn't going to solve this problem, which means that waiting isn't the answer. What you do need is point out his pattern of putting work ahead of you.
Next tell him that his actions are a form of communication. Because actions can be interpreted in many ways, he needs to translate his behavior into words so that you can understand what he's telling you. Keep in mind that he may be unaware of the thoughts and feeling that drive his behavior, so you may not get very far at first. But do keep asking the right questions, which will help open up his mind and assist him in becoming more and more self aware.
I would also consider telling him that he seems to be running scared. The fact is we all have mixed feelings about getting close to others. This fear can be expressed in many ways, from physical distancing, to behaving in ways that drive the other person away or burying oneself in work, to name but a few manifestations of the fear.
If you study his behavior towards you, you can see that he has pushed you away from the beginning by not keeping his promise to clean up his house, which was so off-putting. His vague comment ('never say never') in response to your question will he move to your area also says that he's scared to commit.
Tell him that he's sending you mixed signals. He says he loves you, yet avoids finding work in your area. Ask him to talk about his mixed feelings. What part of him wants to stay away? Is he afraid to move near you and see the relationship fall apart again?
When you get him talking, you will know where he stands, which will put you in a better position to evaluate your options. Good luck with him.