I read that you said that "the more FIXes she gets the more horribly she treats me"...
What the deal is this. In my sitch where I've basically lost my female companion and all that comes along with it. A part of myself was stripped, so I would give up on myself at times.
By starting to talk with the opposite sex, and understanding that things can go further. Without taking anything in a "cheating" pleace, talking with them was enough to help me stand up for myself in the situation. The reason is, I know there are women who will take me as I am.
I started to thinking about it, if I started cheating on my WAW at this point - I could turn as ugly as her in our interactions. My thought would be, that she left me, that she treats me like crap and I'm not even worried about her, because I'm getting mine and if its a real relationship her games would look like childs play, and I'm sure I would be disrespectful.
So I'm sure she's treating you worse and worse the more along she goes. These other guys who are getting a piece of her, are the real prize in her life she carved out for herself.
Most of us got the same treatment and the further along they get into it, the worse the treatment gets.
I'm not sure what you can do to help your esteem here, but talking with the opposite sex especially if its ones that may be open to you, will give your brain piece of mind that you know later if it comes to it that you will have options and your life will be fine. It will take away the firepower that your wife has on you.