Who is Chris Mortensen from One True Thing and what is their importance?

Chris Mortensen is a man whom Ellen remembers from high school. She meets up with him at Smitty's bar on Good Friday and lets him buy her drinks. Later, the two have sex in Chris' double-wide trailer when Ellen "wants to feel something". It is clear that Chris wants more from the encounter than what Ellen is interested in giving. He attends AlAnon meetings for his alcoholism and eventually dies when he is struck by a drunk driver.