I hope my MIL gives me some family time

I am not saying my MIL is a bad person, but I hope she can give some family time for me to be with my son.

I am 43, my wife is 36, definitely we know how to take care of our own 5 years old son. But just yesterday, for example, I know I cannot but to smile and welcome her to our house again, when she has already had the weekdays to take care of my son.

My wife and I take turns to give her a sum of money monthly to babysit for us in her house when we go to work.

But during weekends, before I can plan any activity to bring my son out, my wife would tell me that her mother is coming to our house.

Not that I do not welcome her, but whenever she comes over, it is like a soft army style of stand by the house. She would pick all the flaws she can find in the house.

For example, she told me that there are ants in the potato chips yesterday, which I don’t find any, she just threw them away and said she would buy some for me when she comes again.

She knows her own daughter seldom help with housework, so I have to make sure the house is clean and tidy before she comes.

She would buy all sort of food for us to eat, for fear we didn’t eat enough on a Sunday. I want my son to use a spoon to learn to eat by himself, but then my MIL would always feed him.

I dare not oppose whatever my MIL does, as I know my wife would be sandwiched between me and her mother if we quarrel.

Can someone advise me on how to build a better relation with my MIL without having to give in anything on my part? Thank you.