The phrase 'doing a Jon Hamm' is emerging to describe a pattern where men express reluctance towards marriage and fatherhood for years, only to later start families with new partners. This phenomenon has been shared by multiple women who recount personal experiences of investing years in relationships, only to be blindsided when their partners commit to others.

The term is inspired by actor Jon Hamm, who reportedly spent 18 years with actress Jennifer Westfeldt, stating he lacked the "marriage chip" and was not keen on fatherhood. Hamm later married Anna Osceola, and the couple is expecting their first child.

Women describe the pain of being a "foster girlfriend," investing time and emotional energy into a relationship, only for the partner to move on and marry or start a family with someone else. One anecdote details a woman who supported her partner through a career change and a move, investing her savings into a business. When she expressed a desire to start a family, her partner demurred, only for him to later become engaged to another woman who became pregnant.

Another account involves a woman whose partner consistently delayed discussions about children, citing various life milestones such as buying a home or career advancement. After a five-year relationship ended, her former partner became a father with a new woman shortly after they broke up.

These experiences highlight a perceived double standard, where men who eventually commit to marriage and fatherhood later in life are often praised for "personal growth," while the women who waited are left to grapple with lost time and fertility. The article suggests that a man's "not yet" can be more trapping than a definitive "no," as it offers false hope that can deplete a woman's reproductive years.

Experts, as cited in the notes, suggest that this pattern often occurs when the new partner arrives at a moment when the man is ready for commitment, or after he has realized that his reluctance is no longer a viable option. The piece advises women to take men at their word regarding their desires for marriage and children, rather than investing years in the hope of changing their minds. The narrative implies that the time spent waiting for one partner may inadvertently be preparing them for another.