The reason that I mention this is that it's very likely that she still has no idea whence came Martha. We know that they met at the summer camp she sent him to because she's too big and important to play referee over the summer. We know that her refusal to finally sit Mike down and explain to him that beating the snot out of Lizzie was bad form led to the stupid fight that led her to impose a weird punishment. This means that we know that she'd more or less invited Martha into her life because she's a terrible parent. It also means that she's trying to shoo her out of her life by also being a terrible parent.
The interesting thing is that history would rhyme instead of repeat when her telling him to get a summer job at the grocery store led him to meet Rhetta. About the only person not part of his life due to her own actions happens to be the one she likes: Deanna.