Difficulties
"Sirius what are we going to do?" She asked in a panicky voice, she looked like she was about to start hyperventilating.
"Well we can't tell him," he answered her, "It would destroy him."
"Your right" she said giving in. They had been debating on what to do for hours.
"How did this get so complicated?" She sighed through the tears that had just started to fall.
"Easy we just got carried away and made a mistake… several times" He answered her.
"Oh why, why didn't we stop?" she cried
"Because we were in the heat of the moment" he replied sadly
"But Sirius there is now PROOF! PROOF of our crime!!" Lily wailed
"Lils," Sirius said in a calm voice, "You can't know that the child is mine."
"The hell I can't!" she responded "I know it is! I can feel it."
"Oh! Merlin!" Sirius followed up with a string of profanities while his Lily cried herself to sleep on his couch.
Merlin, how could they let this happen? What kind of a friend was he? His best mate was being worked to the point of exhaustion during his Auror training and left a wife home alone. Sirius was ordered to keep her company and keep her safe NOT seduce her. That is what happened though…
James always busy and when he was not busy he was always too tired to pay attention to his new wife. At least the kind of attention that a husband should pay to his wife, especially a wife such as Lily. So, Sirius unintentionally filled that void for her, at least at first it was unintentional.