As long as a person is working as a geisha, they must remain single — hence, a geisha must not get married. The only thing they are allowed to be "married into" is their art or profession. If a geisha actually wants to get married, they would have to quit or retire as a geisha and this is celebrated through a ceremony called hiki-iwai. Once they quit, it's not possible to come back as a geisha but it is possible to become an okami-san (proprietress of either an ochaya or okiya). This is often the norm in places like Kyoto, but there are now a lot of places in Japan like Tokyo that allow married, divorced, and/or women with children to become geisha. Likewise, maiko are not allowed to have boyfriends.