Annoyed of MIL

My fiancé and I have an argument about his mother every single time we're around her... Which is now... He's being an ass and ignoring me, so I refuse to talk to him.. It's always a constant argument every time... It'll be because I'm not comfortable being around her, the way she baby's him like he's 5 and the way she depends on him like a husband... Most of all, the way she wants to control the way I want to raise my daughter; which will be her first grandchild.... What should I do? I keep reading that the husband cleaves to his wife; but in this case he hasn't... Idk what to do anymore