Years ago my MIL was widowed, twice. Then she married Lawrence. They were in their upper 50s. They signed a prenuptial. She owned a small house in town. He owned a farm with buildings. They lived on the farm for 20 years and he died. Lawrence's Sons got the farm. She got her house in town. She was allowed to live on the farm as long as she didn't remarry or until she wanted to leave. No do overs. She stayed there 5-6 years, then moved back to her house in town.
They got along great with it. I, like you, always thought it a bit weird.
When I married Terry 20 years ago we didn't do a prenuptial. I had considerable fixed assets. She had minimal fixed assets. We are fine with it. We completely trust each other.