When Seeley discovered Rebecca was pregnant he asked her to marry him, but she refused. It is later revealed she refused the proposal because she did not want to be "one of those women" and did not want to be judged. She later reveals to Temperance that she now wishes she had not missed her and Seeley's "one true moment" and wonders if he feels the same way.
She often gets quite annoyed at Booth, but does not seem to have an aggressive personality, only an vindictive one, as proven in S02E02 when she threatens to use the legal system to keep Booth from seeing his child. This is demonstrated when she struck up conversation with Brennan, although it ended in her leaving without letting Booth know she was there. She seems to be a good parent, with Parker never showing specific disdain to her, only her boyfriends. She also prides herself on being an independent woman, citing this as being another reason she didn't accept Booth's proposal.
After Rebecca and Booth ended their relationship that resulted in Parker's conception, they were distant, Booth saying that he missed many of the milestones during Parker's early years. However, Rebecca has had sex with Booth since then, admitting in Season 2 (When Parker is 5-6) to having sex at least three, maybe four times that year. In that same episode, they mutually agreed that they were over, Booth stating they "cannot end up groping each other in the FBI closet." In the same episode (The Truth in the Lye), Rebecca lets Booth know the true reason that she did not marry him, reassuring him he is a good father to Parker. Rebecca sometimes appears in the series with a boyfriend, but often Parker doesn't take to them, preferring the company of his father.