My take on Winona Kirk...
Every time she looked at him she saw her husband. It was worse on his birthday, because it was the day. The day he died to save 800 people. Died to save her. Died to save their son.
So after years of pretending, trying for Jimmy's sake, she finally gave up. She fled back to the stars, back to where she felt closer to her husband. She loved her children, she truly did, but she loved her husband more.
So when Sam ran off, she felt guilty. When Jim almost died, again, she cried.
But she stayed among her stars.