Q: My son has a phone and ipad that he uses my apple id for purchasing etc, now my emails and textxt are going to his devices. How can I stop this but still let him use my account for purchases etc?

Have a look.. Here-

You need to delete the iCloud account that is set up on his device with your Apple/iTunes/iCloud ID. He can still purchase items from iTunes as long as your Apple ID is signed onto the iTunes & App Store:

Settings>iCloud - delete the iCloud account

Settings>iTunes & App Store - make sure your Apple ID is signed on there

You might want to consider getting him his own Apple/iTunes/iCloud ID. You can still put your credit card info on a new ID which would allow him to continue to purchase items with, but would keep his and your other things (like mail, messages, etc.) separate.

Cheers,

GB