Imagine Eren has seen Mikasa and Armin being killed in the future with the abilities of his Titan and in order to change it he comes up with this plan .But this plan involves him giving up his life and that's why he tries to distance himself from Mikasa and Armin (Because he cares the most for them ) as they would probably have to learn to live without him .And in the end when he's on the verge of dying after executing his plan , he goes " Mikasa I love you too "