I'll help Christie!! Just let me know when.

I agree with Christie a little on this one too. Certainly don't let MIL disrupt your routine or let her just take DS whenever she wants. But as you get more used to having her around DS (and bub) you might feel comfortable enough to leave one or both of them with her for short spells. I am speaking from experience on this one. My ILs recently moved here from interstate and prior to that we had no one to help with the boys. Now I really appreciate a helping hand occassionally. THis week for example when Tom was sick, she came around to help with the washing. When both boys were asleep she stayed with them while I went and got some groceries as Tom wasn't well enough to take to the supermarket. Then when they woke up, she spent time with Tom so I could have some one on one time with Jack that we'd missed out on with Tom needing so much attention. She doesn't necessarily agree with the way I do everything, but she goes along (apart from buying them too many clothes and toys, she can't help herself on that one).

I would start by explaining that you have certain routines so there are only certain times when it suits for them to be around. Just tell her DS gets too disrupted if the routines are changed. Also explain that you have never left DS before, so you will need some time to get used to the idea, and for DS to get used to it. And also that there are certain ways you parent and ask her to respect that. I am sure most MILs will agree to go along with the parents as they don't want to risk missing out on their grandkids.

Good luck with it, I hope you find the right balance.