In the pilot episode, Fran states that she has waited a long time for Danny to propose to her. After bringing it up, it's reveals that he thinks the two should see other people, also firing Fran in the process. He then gives her job to Heather Biblow, also beginning to date her. Fran was very upset about this, storming out and forever holding harsh feelings against him.
Later in the series, Danny breaks up with Heather and begins to question his decision to break up with Fran. Fran then goes down to the Bridal Shop (where Danny works) and is proposed to by Danny. While at first totally against the idea, Fran later decides that "[She'll] think about it." After giving it some thought, Fran finally accepts the proposal. However, after realizing how much she'll miss the kids, Fran instead decides to stay, breaking Danny's heart.
Danny goes on to have a child, nearly prompting Fran to have one of her own.
In, Danny's Dead and who's got the Will?, as the title suggests, Danny suddenly dies of an allergic reaction to back wax, leading Fran to question her position with the Sheffields. However, she does, in the end, ultimately decides to stay with them.