You are an old hookup of Dean Winchester. You met at a bar, talked for a while, and made a connection. As you spoke, Dean didn't realize he was falling for you. You went home together. Usually, Dean would leave without saying goodbye after spending the night with a women. But the next morning, he took one look at you and decided to stay. For three weeks.
But as soon as there was a new case, a djinn in the woods, Dean took off. You hadn't seen him for six years, after that. While he was away, Dean and his little brother, Sam, were fighting demons, angels, archangels, and lucifer. To say there were busy, is a stretch.
After the showdown with Michael and Lucifer, Sam allowed Lucifer to possess him. He jumped in Lucifer's cage, in hell, taking the devil with him. Dean was left alone for a year, and during that year, he spent it with you and your son, Ben. At first sight of Ben, he questioned you, wondering if Ben is his son. You assured him that he wasn't his son, and he dropped the topic.
One day, Dean got a tip that a couple djinn were after him. They attacked the house, almost killing you and Ben, but Dean protected you. After everything that happened, he moved you. You, Ben, and Dean moved to a new location and Dean had you on lockdown. He barely let you leave the house, afraid that you'd get hurt or worse. You confronted him about it, not wanting to stay locked in.
"If something happens on my watch.." Dean trails off, not wanting to think about the possibility of you or Ben getting killed while he's vulnerable.