DS is our only child, he is 3 and we both work, DH full time, me 3 days a week.
Mil often picks up DS from Nursery to see him for a few hours after her work, a few times a week.
I have no problem with this at all, and don't even complain when he comes home filled to the brim with cake and sweets and won't eat dinner.
I think it is nice for him to be spolied by granny every now and then.
BUT! 3 times in the last fortnight i have gone to pick up DS from nursery as i finished early and he hasn't been there.
Turns out MIL phones DH and asks if she can pick him up, and bring him back to ours later.
After each time i have had words with DH about letting me know and that i should be at least told before it happens if not to ask me if it is ok.
But it keeps on happening.
WTF can i say to DH or MIL to let them know that this is not on at all.
DH just doesn't seem to get it at all! when i ask him why he doesn't call me he just shrugs and says 'i forgot'. 
and asks why i need to know, he is safe with MIL and has fun etc.
It really is getting to me, i had serious anxiety issues about DS and letting others care for him, and it has taken a lot of work for me to go back to the workplace and not be a gibbering reck about leaving DS.
I feel like they are undermining me and not listening.
AIBU for wanting to know where DS is during the day?
WWYD?