After the 61st Games
He married Cecilia when he was 19 and when she was 18. This happened during her victory tour.
They were very happy together, but shortly after Katniss's trick on the berries, Cecilia was reaped for the Games. This broke his heart, as he had to raise the 3 kids by himself.
76th Hunger Games
During the rebellion in District 8, he was one of the many civilians there who joined the rebellion. Because of this, he was killed by the Peacekeepers, two days before the remaining victors would die in his District. This left his kids without a parent and they were sent to an orphanage.