Reason she will stick with Dwayne Wade
To put it simply Gabrielle Union will stick with Wade because she perceives him as an alpha male, and she's in her 40's which makes her window of having a healthy child without genetic defects ever the more shorter. In short she does not care about Dwayne's personality, or actions at this point and has invested too much time in the relationship as it stands to abandon it.
Dwayne brings to the table social status, money (greater than hers), and strong genetics, so whether he abuses her,cheats on her, or treats her like *beep* she will continue to stick with him.
Now some of you might be going well she's rich too, famous and popular, and could get another man like that. However, most men while they may bang a 40 year old, or date, they will not commit their lives to one if their more than capable of scoring a hot 20 year old.
Even if she finds one, she will have to spend more time investing in this new relationship, which she doesn't have at the moment; remember her biological clock is ticking.
Gabrielle based on how well she's kept herself in good shape for her age , and could get another guy at drop of a hat to marry her. However, the likely hood of snagging another alpha like Dwyane would be very small, and like most woman setting for a man with lower attributes (looks, money,social statu) despite him being faithful,kind,and good husband/father to her kid would be doing a disservice to her.
So in short Dwyane could give her AIDs, beat the crap out of her, nearly kill her, and she'll still stick with him.