My ex is finally on board
.
The turning point for us was when he started to bring my dd8 to a Sunday math club and actually stay for the sessions. Most kids in this club are 3+ years older than my dd and the subjects they are studying are not "normal" school curriculum (mostly problem solving, number theory and other advance topics).
Just a year ago he swore under oath (in court) that she "was just a normal kid and wasn't gifted at all". Now he drives her to her math club and her robotics meetings every other weekend. He is teaching her computer programming (his field), volunteering at her school and actually discussing and showing interest in her schooling. He actually made a comment that our dd was very fortunate to be in the school she is in right now (never mind the fact that he fought very hard to get her out!)
Who knew that simply forcing him to observe her in a math club would achieve what a court couldn't do?
