Ex and claiming son

How do you guys work it out between each other?

I have a 5 year old son with my ex. He has always had him on his insurance so he always claimed him. Well now I have pretty decent insurance as well so now I think we should switch off having him on our insurances and claiming him. He agreed to it years ago. He said whoever has him under their insurance, can claim him now he’s not letting that happen. I don’t wanna go to court over this cause it’s silly. He’s a spoiled rotten ass so he will do whatever he has to to get his way.