That is one possible scenario.
Another is, she met this man at a business conference and went to bed with him. She is not on the pill, her husband normally uses condoms but in the heat of the moment and her desperate need to feel the strangers black cock deep inside her, she believed him that he would not cum in her.
The intensity of their lovemaking and her orgasms with the stranger, shock her and mask her senses to the strangers own shuddering climax when he releases spurt after spurt of his sperm into her.
It is the tell tale trickle of wetness down her thigh that signals his promise was not kept. She starts to mentally calculate how close she is to her fertile period.
He leans close to apologise and their kiss comes from that