I am currently not working due to recent major heart surgery. My ex-partner is aware of this and has decided now that she will organise our son's orthodontic treatment (this has been on the cards for 12 years). Previously, I had been happy to pay my portion should she provide a detailed quote from the orthodontist as I have some health insurance, but she refuses to provide this to me and just keeps telling me to pay half of 15k. Nobody in their right mind would just hand over this sort of cash, especially as she is long-term unemployed, has a documented history of drug dependence and mental health. She has advised me recently to pay her the money or she will go to Child Support. She has now sent an application to Child Support for this. My questions are: 1. Do I have a right to object to 18-year-oldold son undergoing this treatment before she starts it in 10 days time? 2. At the very least, do I have the option of requesting she shops around? She has selected the most expensive option as she can pay it off interest free and get a lump sum of cash from me. 3. Can she really just go ahead and do this against my wishes and then get money off me after the fact? Thanks for your time.