Honor is a writer and mother who is intensely focused on having a second child despite medical complications requiring the removal of her ovaries. Her fixation on expanding their family heavily strains her marriage to Tom. She serves as the story's unique first-person narrator, offering continuous observations of her family's circumstances following a tragic separation.

Tom is a finance professional who becomes a devoted stay-at-home father to his son Henry. He struggles to handle intense feelings of sorrow and isolation while attempting to rebuild his routine. Desperate to maintain stability, he often avoids difficult conversations and hides from painful memories.

Grace is a sommelier-in-training who works at a wine shop and runs a grief support group called Sunday Blues. She carries the weight of a past tragedy involving her late partner, Pietro, which keeps her isolated from romance. She exhibits authenticity and openness, capturing Tom's attention due to her physical and temperamental similarities to Honor.

Annie is Honor's best friend since their university days and a constant, stabilizing presence in Tom's life. She is outspoken, fiercely loyal, and unafraid to confront her friends when she believes they are making reckless decisions. She frequently hosts Sunday lunches for their social circle at her home.

Lauren is a neighbor and close friend of the Wharton family who provides immediate support during difficult times. She harbors resentment toward her ex-husband, Daniel, and often relies on Tom and Honor for emotional grounding. She is deeply invested in the daily dynamics of her friend group.

Colette is Honor's mother, a Parisian woman who maintained a distant relationship with her daughter since sending her to boarding school years ago. She carries her own complex history with illness. She eventually steps up to become a steady guide and caretaker for her grandson, attempting to atone for past absence.

Chloe is Honor and Tom's four-year-old daughter. She is energetic and sometimes a source of mild friction between her parents when her immediate needs interrupt their tense adult conversations.

Henry is Tom's young son, a left-handed boy who becomes the absolute center of Tom's world. His existence gives Tom a renewed sense of purpose and a reason to completely alter his career path.

Jess is the surrogate working with the Wharton family to help them have a second child. She is compassionate and supportive, offering Tom vital comfort during overwhelming moments as they prepare for the baby's arrival.

Oliver is Annie's husband and part of Tom's core friend group. He is generally more impartial than his wife, participating in their regular Sunday lunches and quietly observing the shifting dynamics among their friends.

Zara is Grace's childhood friend whom Annie and Lauren initially attempt to set up with Tom. She is candid about her own romantic interests, specifically her crush on her nanny.

Pietro is Grace's late boyfriend who passed away from a heart attack at a young age. His sudden passing profoundly altered Grace's life trajectory and left her dealing with long-term grief.

Daniel is Lauren's ex-husband who betrayed her by maintaining a secret second family. His past actions leave a lasting impact on Lauren's emotional state.

Judith is Tom's mother who resides in an assisted living facility due to dementia. Because of her cognitive decline, her family shields her from painful truths about their current circumstances.

Katie is a nanny who captures Zara's romantic attention. Zara's feelings for Katie prompt her to decline a potential setup with Tom.

Blanche is a member of the Sunday Blues grief group. She provides insight into the group's dynamic, revealing they continue attending primarily to offer Grace emotional support.

Nellie is Grace's coworker at the wine shop. She is delighted when Tom offers to help them with the shop's finances, eagerly giving the pair space to connect.

Richard is Colette's late husband. His passing deeply affected Colette, informing her perspective on love and loss.