Sounds like the tvshow Everybody Loves Raymond. Things like this can get to be a habit, and then they will say they are coming over so YOU don't feel bad. I get it about the longer rather than shorter - I need a long stretch of time to myself or else I get nothing accomplished, I feel anxious.

It's YOUR life. They have had their go. You wouldn't do this to a future DIL. It will be scary and they may get angry and cry or retaliate - or they may do as my mother did and say, well, if it was what you wanted, YOU should have said so, don't blame ME now, you just didn't want it bad enough! So respect YOURSELF - and give yourself and your kids the life YOU want for them, not one defined by old people. If they want to help on your terms, great. They want to see the kids, hopefully they go along. Good luck!