How happy, or unhappy, do their lives eventually become for Elinor and Marianne?

By the end of the novel, Marianne begins to see the Colonel in a more favorable light, and they marry.

When Marianne is hurt by Willoughby, she hides nothing, and shares her misery with the house, everyday. But Elinor wants to spare her family the pain she is suffering. Perhaps as a reward for this behavior, Elinor marries Edward, her first love, whereas Marianne marries the Colonel.