“Dear Sugars, I’m a serial codependent. I’ve married and had children with two addicts,” begins a letter signed by “Mommy Messed Up.” Over the years, her second husband began to withdraw and stash money inside of old bottles. Now Mommy Messed Up is ready to end their toxic relationship. The only problem is she’ll have to disrupt her children’s lives for a second time. “I’m fine with breaking my own heart,” she writes. “But how do I break my boys’ hearts?” A second letter comes from a woman who is haunted by her abortion, a decision she laments now that she’s experiencing early menopause. Both women are ruled by their regret. In this second part of our series on moving on, the Sugars and Dr. Harriet Lerner discuss how we can release ourselves from our past mistakes and move forward despite our deepest regrets. For more information on today’s episode, including a list of literary recommendations from the Sugars, visit nytimes.com/dearsugars.