You are not in a unique situation.
Many women involved with married men, if not all, hear that there is a future, when 'this' or 'that' happens. The point being, that future never comes.
In your case, he also has a second adultress on the side, who decided to have a baby with him, likely to keep him coming back, maybe for 'security' so to speak. He would have given her the 'future' as well.
You in the meanwhile, are in third place. Behind his wife, and behind his second woman. What do you think the chances are that things will filter down through years of waiting, to finally include you as the primary wife in his life.
He has been cheating with the second woman for at least six years.
What kind of person do you think he really is, and please tell me why you would consider waiting for such a man, who cheats on two other women, has children, and lies constantly? Why would you buy what he's selling, and have you considered a few other things.
There are children here that will sadly be the result of broken relationships. They will eventually learn they have a father who lied, cheated, and taught them nothing of how to live an honourable life without hurting people. Such men should never have children in my opinion.
While he juggles three women at a time, which one is likely to get hurt the most. First, it will be his wife, then it will be the second woman, then it will be the third woman. All three of you are wasting your lives on relationships that have nothing of substance, whether realized at this moment, or not until down the road a bit.
Do you think he will be a different person after his wife and first lover dump him- while you take him in? Will waiting for something that may never happen, you are missing living your own life. Everything you have to do with this man, revolves around cheating- including you.
Not to mention that I don't think there is anything worse than a woman stabbing another woman in the back, such as you've done with his wife. You don't have any control over how many other women this man sees, but you certainly should know enough not to mess around with a married man. That one woman would cheat with another woman's husband, is the worst betrayal.
Try to rise above this very low place you are in. Realize that no good will come of this relationship, and that with or without you, the man you are involved with will eventually end up in divorce court, and be saddled with child support and debt for the rest of his life because of his choices. Don't let his choices, determine how your life is going to be- if it ever happens, which it likely won't.
Don't allow yourself to be used by him, and get out. Make it a new, higher standard that you will never again get involved with a married man. See him for who is is, not what you think he will be, when he is with you eventually. Which will never happen anyway.
You are wasting precious time allowing yourself to accept the worst possible behaviour from a man. He is in self- destruct mode, and will take you with him.
Raise the bar, set higher standards, and drop the married, double cheating man. You can't change him, but you can most certainly change yourself.