Why does my wife's partner visa application require information about my daughter and my ex?

Hi, I am applying for my wife's 2nd 2.5 year partner visa and they are asking if I have children with another person. I have one daughter from a previous relationship and have had standard access since she was born. Nothing changed when me and my now wife got married 2.5 years ago. Visa application Gov.uk is asking loads of questions about my daughter and then asking for evidence of my wife's contact with my daughter. Also a written signed letter from my ex saying its ok, also utility bills from where my daughter lives with my ex!!! Never seen this before! What the hell! Who asks their Ex to help them with their new wife's visa! There are no issues at all with my daughter visiting us. But I still dont really want my ex in our private business (Visa application) Can anyone advise on this bit. Can I ignore the request for signed letters and utility bills etc?