Emotionally unavailable guys always start out by proving to you through their actions that they have the capacity to be everything that you ever wanted. They'll talk about how they see a future with you, but never really do anything to act upon it. When the relationship naturally takes a new level or when it comes to a point where more is asked of him - he needs to be more responsible, accountable etc.. - he pulls the rug from under you by recoiling suddenly and without explanation. And because he knows that you are broken and validation hungry, he banks on the knowingness that you will view his withdrawal as something YOU must have caused by simply not being good enough. Once you're at this point, he can pretty much do whatever he wants and just like that, everything is on his terms and you're a professional doormat.
When a guy changes suddenly, you have to understand that you will never be able to make sense out of it, so stop wasting your time. It's insane and no good sense can ever be drawn from insanity. There is nothing that you could have done that would have so much clout that it could make your "soulmate" go from loving and respectful to royal jackass. People don't change. Over time, they reveal themselves. Because that's what people of the emotionally unavailable type do.