Actress Expecting a 'Little Princess' with Boyfriend Matthew Koma . RELATED VIDEO: Hilary Duff's 5-Year-Old Son Luca Blows Kiss While Water Tubing “I'm cherishing the now,” she continued, joking of what the future. This is the first child for Duff and her boyfriend, singer, Matthew Koma. The couple has been dating on-and-off for several years. In December. Hilary Duff Rekindles Romance with Matthew Koma – See the Pics! They first sparked dating rumors in after working together on her.