Though much research explores the use of a romantic partner as an attachment figure during the course of a romantic relationship, there is little research assessing whether individuals use their former partners as attachment figures following relationship breakup. The three studies specifically examined whether individuals use their former partners to fulfill the attachment function of secure base, as measured by willingness to explore and feelings of felt security, and which factors may affect the ability to use the former partner as a secure base. The first study examined whether individuals used their former partners to fulfill the attachment function of secure base, compared to close friends or acquaintances. The second study examined whether perception of permanence of the breakup influenced the ability for individuals to use the former partner as a secure base. Finally, the third study examined whether individual differences in attachment style underlie an individual's perception of permanence of the breakup. Findings indicated that older individuals experiencing high levels of negative affect do indeed use the former partner as a secure base compared to an acquaintance and close friend and younger individuals experiencing lower levels of negative affect. Individuals primed to feel high perception of permanence with regard to the former relationship used the former partner as a secure base compared to individuals who were primed to feel low perception of permanence, who experienced lower levels of felt security. Finally, individual differences in attachment style did not predict differences in perception of permanence, though insecure attachment styles were associated with changes in partner perception, which has implications for secure base use. Results are discussed in the terms of adaptiveness of maintaining a tie to the former partner following loss, and the implications of this tie with regard to an individual's changing attachment hierarchy following relationship breakup.