There are those out there who are going to argue "alpha" is a made-up word. Then again all words are "made up", but that usually escapes their notice...
There are people like this out there. Some dommes seem to have a hard time landing one because they aren't willing to invest the time in earning the trust and devotion of people like this. They think that simply because they are a domme submissives should be begging to serve them. Except the type of person you are seeking is not normally going to throw himself at your feet.
Why? Because you are asking for a man who is both willing and capable of standing on his own two feet, who is successful on his own and while he might crave feeding his submissive side, he isn't going to throw the rest of himself away just to feed it. He has too much pride and respect for himself to do so.
The question is, what are you willing to do to land a partner like what you seek?