You cannot control the actions of another person. You are turning yourself inside and out, trying to figure out just the right way to "be" so that you can avert disaster. This is *precisely* what she is running away from. She doesn't want to live with a manipulating, uptight, overly controlled individual. I'm not saying to suddenly morph into a footloose and fancy free hippie--that's not really you and, after all, she loves YOU. But if you hope to have any success you will have to fight against this tendency to spaz out and attempt to manipulate each and every moment with her. Believe me when I say that she sees through it as if it is a sheet of glass in front of her.
Try to calm down and tell yourself that she may indeed be gearing up for a final decision. Then again, she may not. What she does or doesn't do is really out of your control, isn't it? Figure out what you want and stay steadfast with that. She gets you all wound up and flustered and tongue tied (and not in the good way either, lol) and next thing you know you are saying and doing all these goofy things. Perhaps if you concentrated on a few mantra-type replies you will feel more prepared and less inclined to try and control. Fwiw, I think what she is doing is pretty crappy. She knows full well your desperation and so she is orchestrating these "conversations" to prey on this. Don't feel like you need to jump every time she wants to talk. You can put HER off you know. In fact, I think it would do her good to see you getting a life and becoming a more well rounded person.
It is good to see you getting in touch with your anger. Keep the anger "clean" if you know what I mean. Don't fall into a poor me space and it will be refreshing for her to see.
I had an instance with my H last night where he was mad but wouldn't admit it. Instead he was picking on our daughters and, in general, storming around (quietly you know, lol) and picking on everything. Finally I called him out and he sat there, confused. He said, You know..I am mad but I don't know what about. I told him to give it some thought and figure it out because he was way past getting on my nerves. He replied that it was because our checking account wasn't balancing and he thought I had spent money and wouldn't tell him. (the fact that I don't do this doesn't really matter) I told him I had nothing to hide--as I had stated before--and he was welcome to look up our account online. He did and calmed down when he got it to balance.
My point is that people like him....(cough)You have a hard time identifying their anger and the source of it. H does not allow himself the freedom of figuring out what is making him p*ssy and then doing something about it. He feels trapped--for some unknown reason to me--and so he takes it out on me but won't own up to the fact that he's angry. I can see and feel his anger from a mile away, though! Anyway, last night went quite well with me holding on to myself and not giving in to the urge to verbally slap him around and him being willing to hear me and figure out what his problemo was and then be *active* about the solution.
All this to say: there's hope for you guys!
Calm down, go work out, have a drink, pray, whatever you need to do in order to chill a little and let the thought settle over you that you cannot, in one conversation, change her mind. I see you flogging yourself over every little thing, such as your mother's meddling, in front of your wife. Instead of trying to control how your wife perceives your mother, why not try to position yourself on her side? Think of the two of you as a team and practice responding to her in that fashion. When she told you about your mom you could respond "What a meddler" or something like that to foster a "us against the world" rapport between the two of you, instead of a "me against you" paternalistic feeling. You know, I hate that H would always try to fix whatever I was saying (still does, lol) but I realized a couple years ago that I was soooooooo guilty of the me vs. you style of speaking that automatically set up the paternalistic dynamic. I made a list of goals and that was one of them: to make my words jive with my purported goal of saving my M. I started using words that indicated that we were on the same side and it made a *huge* difference.
Well, I no longer know what my point was so that means it's time to sign off.
have a hard time identifying their anger and the source of it. H does not allow himself the freedom of figuring out what is making him p*ssy and then doing something about it. He feels trapped--for some unknown reason to me--and so he takes it out on me but won't own up to the fact that he's angry. I can see and feel his anger from a mile away, though! 
