What happened to me and what I see with many others is that they are deliberate while they attracting something. They do active something to feel better, they start loving themselfs more, they remind themselfs all the time that they are deliberate creators and when the thing/person comes they fall back into reaction mode, complain about the behavior of the person, analyze what they said, feel bad and powerless about it and so on. Of course they can't maintain it, because their vibration is so different from the vibration they had actively worked for before. It's law that it has to fall apart again.
So what can you do about it? Don't stop doing what you were doing in the attraction process. It's not something you do once and when it's done, you can lean back. You are never done with anything. You can loose everything and you can gain anything you want. I think the most important thing is to never forget who you are, never forget your power and always make the way you feel the most important thing for you.