I've logged onto iTunes, but it's asking me security questions because it's a new device, and I'm getting the answers wrong, but iTunes wants to reset but send the new passwords to my ex partners email address how can I get round this.
I believe part of the recovery process is you get an e-mail allowing you to reset questions. If that e-mail isn't correct either because your son set it up then you really have no option but to ask Apple again. They are getting strict abotu security and given the number of "My iTunes account got hacked" posts here I can guess why. They have no way of knowing you really are the owner of the account. It's like me going to a policeman and saying, "See that car over there? That is mine, can you open the door for me?" and the police opening it on that basis alone.
Frequently asked questions about Apple ID - http://support.apple.com/kb/HE37 --> Can I change the answers to the security questions for my Apple ID? --> Yes. You can change the answers to the security questions provided when you originally signed up for your Apple ID. Go to My Apple ID (http://appleid.apple.com/) and click Manage your account.
Forgotten security questions - https://discussions.apple.com/message/18402551 and https://discussions.apple.com/message/18625296
More involved forgotten question issues - https://discussions.apple.com/thread/3961813
Kappy 09/2012 post about security questions - https://discussions.apple.com/message/19569468
John Galt's tips (09&11/2012) - https://discussions.apple.com/message/19809294 and https://discussions.apple.com/message/20229239
If none of the above work, contact iTunes Support at http://www.apple.com/support/itunes/contact/ and follow the instructions to report the issue to the iTunes Store.