As the homework gets more complex for the girls I'll be the one better equipped to help.
I dont help my kids out on their homework except if they have some small vocabulary questions regarding instructions. My parents never helped me. Kids are taught in school to the level of their homework. They should be able to do it without much tutoring from parents. What parents need to do is enforce consequences if they slack off. I know what their capabilities are and can detect easily if they are being lazy.
I used a bit of personal responsibility reminder logic last year on my son when he told me he did not want to do his homework one night. I said "That is your choice. But remember what will happen tomorrow when you dont have your homework done". He grunted and went and did his homework. Sometimes they need subtle reminders of the consequences that could await them.
I also dont go digging through their packs to figure out if they did their work. I have them bring it to me when they are done and sign it off.
CTH...You need to grow a spine and take charge of this NOW! Who gives a crap if your STBXW gets her feelings hurt?