By the end of The Hunger Games, Katniss has lost her sister, Prim, to a bombing that reminds her of a trap Gale helped design. Her eventual future with Peeta grows out of that loss and the question of how she’s supposed to keep living after the war.
Gale knows the life she fought to survive. They hunted together in District 12, kept themselves alive through practical skill, and shared an anger at the Capitol. As the rebellion progresses, his willingness to accept devastating costs becomes harder for Katniss to live with.
He helps develop bombs designed to explode twice. The first blast is meant to draw people in (rescuers, medics, bystanders). A second, delayed explosion then kills those who come to help.
This is the same basic strategy used in the Capitol bombing that kills Prim. Gale doesn’t personally detonate that specific bomb or intend for Prim to be there, but he is directly involved in creating and advocating for that kind of double-exploding weapon. Katniss learns about his role afterward, which becomes a major reason their relationship collapses.
Peeta’s connection to Katniss reaches a different part of her life. Their romance becomes a survival strategy in the first Games, but his feelings are genuine. He sees a person whose life matters beyond what she can do for an audience or a rebellion.
The Capitol’s hijacking of Peeta damages that relationship, too. Katniss has to reckon with what’s been done to him and whether they can find their way back to each other. Their future takes time and recovery.
In Mockingjay’s epilogue, Katniss and Peeta have children. For someone whose life has been shaped by the threat of children being sent to die, building that family means allowing herself to imagine the life they’ll get to live.
