My Friend, "Dee", had a problem when she was a newlywed.... her MIL kept "popping in". Dee worked 11PM to 7 AM 6 nights a week, her Hubby, "Doug" worked 7 AM to 4 PM 6 days a week. They only had Sundays off together and spent that day doing laundry, housework and grocery shopping.
Problem was MIL would pop in 3 or 4 nights a week and would stay until Dee left for work. Then on Sunday, the whole family would Pop-in... to "check" on the newlyweds. MIL would also use these pop-in visits to ask/bully Dee about when she and Doug were going to have babies...
Dee finally stopped it by telling MIL flat out, "If you don't stop popping in and surprising us, you're NEVER going to have any Grand-babies, as we have no private time together"! It worked.