sons jealous of me coaching other kids

hi 

im coaching my sons U6 team and recently he's been getting very emotional at the sessions, it turns out he is getting very jealous of the attention i have to give the other kids and its really disrupting the sessions 

has anyone else gone through this and do you have any advice ? we've tried putting him with the other coach but he just walks over to my drills etc 

thanks in advance 

paul