I braced for a bittersweet ending and got the happy ending I wanted.
They lost 5 years of time because of her crippling self-esteem issues. A little disappointing, but understandable given that she likely suffered years of abuse and this absolutely ruined her growth as a person. Their time together in high school was probably incomparably short (but relatively sweet) and the guilt of almost causing his death crushed what little self-esteem she had.
Now they should make up for those lost 5 years, by staying together for at least 50+ more, and as long as their lifespans will allow.