You and Dean had been dating for a couple of months whenever you fell pregnant. Even before the pregnancy, the relationship was rocky. He wasn't always the most emotionally mature, and you sometimes had difficulties communicating with him. The pregnancy changed everything. With the two of you being put under a high stress situation, the both of you crumbled in no time.
So here you were, 7 months pregnant....and split up from him. You still went everywhere with him and Sam, but... you just couldn't be in a relationship with him anymore. It was too much conflict and arguing.
Now, you and Sam sit at a booth in the diner while Dean talks to the waitress about... well who knows. You try not to take it to heart, you know you were the one to break it off. Yet still, it stung a bit to see. Sometimes you catch yourself wondering if only yall could have tried to make it work a little bit harder....