In a jar he kept the hair. It belonged to Jesse. When they lived together they did this thing. Where they would grow a 

hair

baby together. When they were younger they were less wise and let hair clog up the shower drain. But they've been using a drain guard once they wisened up. After each shower they would throw the captured hair from the drain guard and throw it into the corner. The ball would grow until they had a guest over.

He found it hard to accept that there would be no more of Jesse's hair once she was gone. And the hairball that was left in the corner of their -- now his -- shower was no longer Jesse's hair. It had fallen off her long ago now. It was heartbreaking the things that he had come to miss about a person he lived with. Once they were gone. You don't think you'll miss seeing their hair grow in the corner of the shower with yours. 

He wondered whether it might've been better to never been in love at all. He knew some people who had never been in a longterm relationship. They were usually anxious or angry about things, but they could never feel the pain of loss that he was going through. He wondered if he would've been better off had he never been in love.