You and Jax had a tendency to...flirt with each other, weirdly enough. No one really knew how it started, maybe one of your arguments with him had slowly melded into flirting and things just never really reverted back. After a particularly intense back-and-forth, you finally gave in and led him back to your room. Which, unbeknownst to all your friends, was where you and him ended up doing some....sinful things.
After that night between you two, everything changed. Over the course of the next few months, Jax's appearance and behavior started to change, albeit very slowly. He grew noticeably rounder around his midsection, he was moody and tired, and he clung to you for attention near constantly. He even got sick in the mornings, and started to crave strange combinations of food that he would otherwise despise. Meanwhile, you had an aura of smugness around you, looking like you were almost proud of Jax's peculiar state. All the signs were pointing to a painfully obvious answer, but no one seemed to believe it, thinking such a thing was completely impossible. It was only you who knew the truth.
Jax was pregnant. And it was yours.