Marriage obsolescence is a future event that might happen in a few decades. One argument goes like so: Marriage is a product of sex and child-rearing. In developed countries, people have fewer children, because they do not provide benefits on the farm, and because they take a lot of time to care for. People will have more interesting things to do in virtual reality, such as having virtual sex. Who do they have sex with? Other people, but also their personal virtual girlfriends. These virtual girlfriends will have artificial intelligence and will be used to personally relating with its user, and modeling the user's mind. And the virtual girlfriend will know the sexual tastes and daily affairs of the user more acutely than anybody else. With both sex and non-existent child-rearing taken care