The female victim was pregnant with a child from her new relationship.
The double murder occurred when the suspect was dropping off a six-year-old child that he shared with his ex. According to police, the child saw the shooting deaths.
“He pulled his ex-girlfriend out to the car and shot her. Then the new boyfriend came out of the house and the perpetrator drove into him with the vehicle and shot him,” police spokesman Henrik Justesen told news agency Ritzau.
Justesen said that the six-year-old girl was sitting in the car throughout the entire incident.
Neighbours called in the shooting to the police, who blocked off the Svendborg Sound Bridge, which connects the islands of Tåsinge and Funen.
Funen Police said that a post-mortem investigation revealed that the 25-year-old woman was pregnant.
The 27-year-old suspect was due to make a preliminary court appearance on Monday.