50/50 custody ex wants to move out of school district

Currently my ex and I live in the same school district, our child goes to the school the district placed him in due to special programs he needed.  My girlfriend and i are moving this next week but actually closer to the school but same city, and my ex informed me she might be moving to a city about 10 miles away if she gets this new job.  My ex is married and I am just with a live in girlfriend.  We both provide my son with his own room and have him the same amount of time 1 week/ 1 week. Even now having him 1 week she still calls me and tells me he is crying for me the day he goes back to her after spending a week with me.  he is 7 and in second grade.  I am not sure if she is going to try to take him out of the school he is currently in but i do not agree that she should.  He is in special education, because of a mild form of autism and does not like change.  Plus he is doing very well in school making a lot of progress since starting there last year.  He has social skill problems and has actually made friends.  I am going to be living where he can continue to go to that school and im afraid she is just going to switch school district to where she is moving without my consent.  We have 50/50 legal and physical custody.  I want to know what to do if she tries to take him out of his current school just because she moves, and how i can get him to stay there.  it would not be in his best interest to move, that will be his 4th school and hes only in 2nd grade. 5 if you count his preschool intervention.  where she is moving would be very inconvenient for me to take him and pick him up from school on my days with traffic and work (southern california - 10 miles can be forever in traffic), and i understand that it will be inconvenient for her to bring him to his current school but she is the one making the choice to move. Our divorce states that we need eachothers consent for any changes but she is not the type to ask and just do, she already quit a job back in august and took him out of daycare without my consent when i pay for half.  So i am worried about her not getting my consent and just doing, she feels even though stated needs consent, just because she is mom she gets all control and tries to control my side too, when we have fully joint physical and legal.  Also my ex besides her husband does not have any family in the area or area that she is moving and my mom lives just down the street from us, which is convenient in any case of emergency getting my child from school, which no one will be able to do if ex moves his school.  Also, his teacher would back me in not moving him schools if not necessary.  I say if she gets this job and wants to move, he stays in same school because that is what is best for him if it was opposite i would let him stay, because i dont want him to have to go through changing schools, you put him in after school care which he is in when she works anyways and if she needs before school care, she can drop him off to me and i will get him to school in the morning, I do not start til after school begins and can take him everyday.  or she may pay for before school care if she chooses but do not switch schools.  she has done this before and then tried taking days away from me when she moved to orange and i lived in garden grove and she thought it was too far for me to take him to school.  i had to fight with her to keep my days even. and do not want to go through that again love having him even and switching schools will not be good for him.