From This is London:
"Maria, now a celebrated American TV journalist, seemed on the verge of becoming Mrs Arnold Schwarzenegger. But in 1984, Arnold embarked on a passionate sexual affair with Red Sonja co- star Brigitte Nielsen, and even took her home to meet his mother, Aurelia, in Graz.
When Maria learned of Arnold’s infidelity, she issued an ultimatum — and, in August 1985, he proposed marriage to her (Brigitte Nielsen, meanwhile, went on to marry, then divorce, Sylvester Stallone)."