According to http://www.iflscience.com/physics/albert-einstein-told-marie-curie-ignore-haters http://www.iflscience.com/physics/albert-einstein-told-marie...: "

According to http://www.iflscience.com/physics/albert-einstein-told-marie-curie-ignore-haters http://www.iflscience.com/physics/albert-einstein-told-marie...: "A few years later, she became romantically involved with physicist Paul Langevin, who had been a doctoral student of Pierre’s." That doesn't qualify as "quickly married his husband's assistant" at all, and they were never even married.