[ga-to-az] Custody Modification And Advice!

Hello! I am the mom of three teenagers. 17,16,and 13, all of which are about to have a birthday. I share joint custody with my ex husband with me being the primary. My kids and I have discussed for several years now wanting to move out of Georgia and have even thrown out there wanting to move to Washington state amongst a few other states decently far from where we are now. We ultimately chose Arizona for my fiancé, Who just got an amazing job offer there and could really open a lot of doors for my son (16 yrs old) but the job/career opportunities for all my kids will be immensely increased also. I also have friends that are like family in Arizona from when I use to live there as a teen myself, that could help with the adjustment period of being somewhere other then Georgia lol. My ex is an illegal immigrant currently filing to become a resident alien (has been trying since2006). We were divorced in March of 2017 so have been doing quite a few years of our original custody agreement. Which I have not been very happy with for quite sometime because I feel like he is in contempt. He never communicates appropriately about what day or time he will be coming and ends up leaving us waiting around the house for hours, no text or call, nothing. and if he does actually show up he shows up and blows his horn multiple time for the kids to hurry outside and then spam call my phone because he is in a hurry and wants me to have the kids run outside as quick as possible even though he has had them waiting around for hours! At time he will com pick up the kids late on Friday supposed to be having them for the full weekend and bring them back 30 mins later unannounced. to the point where if my fiancé and I were on a date and had to leave restaurant or turn our vehicle back around to go back to the town where I can pick the kids up. I use to be a manager in a fast food restaurant and we would occasionally do our transfer at the restaurant. I haven't worked there since the beginning of last year, and he left my youngest son at the restaurant alone without me there because he was in a hurry and had to leave, but because he guesses i had friends there then he would of been safe. The manager on duty called me and told me that my son was sitting up there and I had to figure out a way to leave work early out of town to go pick him up. just no communication at all, and the amount of times I've had to wait on him to decide to pick up the kids is horrendous. not to mention the amount of time I had to take off of work to drive the kids to his house which is only an hour away. my oldest daughter is about to be 18 in a couple months and she is graduating this year as well!! she hasn't been to stay at his house in a couple years, due to personal reason of not getting along with him and things he has done and said to her. my second oldest who is about to be 16 goes occasionally but he prefers to work his part time job or play soccer. he likes to go but doesn't go every other weekend like our paperwork says. my youngest goes most often, but with us discussing the want to move over the past couple years he has made it extremely clear that he wants to see his dad occasionally but he wants to stay living with me.

anyway, my kids are nervous about the move but are super excited for the change and experience. my ex is absolutely going to contest this modification. any advice on getting the judge to approve the kids moving?? I do not want to separate our family now seeing as my fiancé and I are about to celebrate our 9 year anniversary. He has stepped up and took care of the kids however needed bought them all necessities, and in total we have 5 children my three and his two. my ex pays child support most of the time but it is usually a few months late. then he will catch up his arrears and then go behind again for months. it is not consistent at all. any advice on my crazy complicated situation? any feedback would be super great!! thanks for taking the time to read all of this and i look forward to reading your responses.. just advice please