The first thing the Doctor noticed about his wife when she stalked onto the TARDIS was that she was really very not happy.
In fact, she looked downright furious.
"Are you alright, River?"
Her eyes flashed dangerously. "Do I look alright?" He shook his head nervously and gulped, not really knowing what to expect at this point. "You idiot! You slept with Marilyn Monroe?!"
Ah. So she had heard about that. "Well-well-well-I-I-I... Uhm... That... I..." He swallowed again, trying to get his mouth to work. "I also sort of got... engaged to her," he squeaked. He could've sworn that River's hand twitched towards her gun, and that was seriously one of the most frightening things he had ever witnessed her do. He held up his hands in surrender. "It was an accident, I promise!"
"You don't see me accidentally getting engaged to Marlon Brando, or or or... David Tennant! What did you expect to happen? For all her talent and charm, the woman is a neurotic flight risk, believe me! I know!"
"Of course you know Marilyn Monroe, why wouldn't you?" The Doctor's nose crinkled. "How do you know her?"
For once in what was probably the only time in her entire life, River blushed. "That hardly matters."
Pointing an accusing finger at her, not so much worried about the gun anymore, he gasped, "Did you sleep with Marilyn Monroe?"
She promptly turned away from him, arms crossed resolutely against her chest.
"Oh, but you did! Look who's calling the kettle black, Doctor Song!"
She whirled. "I didn't get engaged to her, you idiot! And I certainly didn't expect it to happen, I just thought it would be nice to talk to her, being as she was one of the most famous actresses of all time. Stop looking at me like that!"
"How am I supposed to do that?"
"For starters, it was a very long time ago, before we were even married. Shut your mouth, it was college, for god's sake!" And in that moment, he could've sworn that instead of being a Time Lord-y human woman, she was the definition of a storm, lightning crackling around her and ready to strike him down in one enormous, wild bolt.
But he wasn't mad. More incredulous, and trying to contain his thoughts about his wife and Marilyn Monroe in the same bed. He always tried so hard not to let thoughts like those get to him in anyway, because they really weren't proper. With an adorable smile that visibly ebbed her anger away, he mused, "Oh, River... you're a bad, bad girl."