there's something to be said about gale telling peeta that katniss will choose the person she can't survive without - a sentiment that katniss notices lacks any mention of love or comfort or affection, only partnership and practicality. because survival is the basis of gale and katniss's relationship - their relationship is the product of an oppressive regime where so many people starve and die and suffer. they built a partnership out of pragmatic necessity - friendship and affection and yes, even love, did spring from that, but nevertheless, survival was the foundation for them, and the fact that the majority of their dynamic is spent in the woods and this is the only place gale sees her happy is symbolic of that.

but her relationship with peeta is extremely different. he gives her laughter and comfort and joy no matter where they are. he balances out the temperamental and volatile nature (a characteristic she shares with gale as a result of their conditions) with peacefulness and an appreciation for beauty and goodness. they have a trust and camaraderie and friendship that extends far beyond the need for survival, a bond that connects them beyond merely the need to stay alive and protect their loved ones. it is with peeta that she truly lives and laughs and loves and betters herself. peeta notices and brings out the most wonderful parts of her cold, dispassionate exterior (mockingjay, suzanne collins), gives her an appreciation for beauty in life (dandelion in the spring, the pearl on the beach, etc). he's the calmness and peacefulness that she needs to truly live and feel free and safe, while gale is violence and storms and outbursts (which she may agree with, but his tendencies to choose violence don't satisfy katniss's emotional needs in a relationship like peeta does).

to gale and katniss, love and relationships and friendships and human connection come second to practical concerns and the mere desire to simply not die. for peeta and katniss, love and life are about far more than just survival, which is why they share an emotionally charged connection that's stronger than what gale and katniss have.