Well, I do not know you personally and probably should keep my mouth shut, but here are my thoughts anyhow..

She's testing you, dude trust me, classic testing strategy. Most humans feel wretched on some level within. Self sabbotage is very common in the human condition. Sometimes, when we tell people we love them they do not believe us due to this inner wretchedness and sense of unworthiness of love, so they sabbotage and test us to see if we really mean what we say. Kind of like the Verizon guy moving to different locations with the "Can you hear me now" she is testing you by doing silly things to drive you away then asking afterward "Do you still love me now?" Driving you away is her way of calling for help. Counter intuitive I know, but we are talking about the rules of love here, logic is illogical.

This woman is much closer to being yours than she wants to admit. You are right to give her a little shake up to remind her that though you are a man, men have feelings and strong ones that must be taken seriously. You are not there to supplement the attention and care and indeed money that she should be getting from the mama's boy boyfriend. Does the mama's boy have nothing to say about the quality time she spends with you? He must really be a mama's boy afterall....

Plus, there are two sides to every story, even this one. Sympathy can be used to manipulate situations and people. Maybe the mama's boy isn't as bad as she projects him to be when speaking with you who will sympathize with her, afterall actions speak louder than words. If he was so bad then her action would be to leave this guy. Something does not add up in between what she is saying and what she is doing. Actions speak louder than words. Only pay attention to her actions.

Many people men and women alike are afraid of being single, they will only leave one relationship when they are certain they can enter immediately into another. I do not know if this applies to her. She is spending time with you because she likes you obviously, that action is undeniable. Why she likes you is a whole other issue. Is it just an ego boost to her to know that someone out there loves her asside from the mama's boy? Is she comforted knowing she has "options," or does she really trully care for you as an individual? Only time will tell how deeply she really appreciates you.

She's testing you to see if you really mean the things you say. You should test her a bit too, really. Not to encourage game playing, but lets' be real, there is always a game the only question is whether or not the contestants are aware of the game or know all of the rules. Not everyone plays the game to "win," some people play just for the fun of it.