Why is he now called Yehonason?
Radak: This is a tradition - before now he is called Yonason (except for 14:6, 8), and after this Yehonason. 1 `
Chomas Anach (Shmuel 2 Perek 1, citing Get Pashut 129:121): A Yud was added to David's name (in Divrei ha'Yamim, and sometimes in other Kesuvim), and a Hei to Yonason's name, to hint that Hashem's name Yud-Kei was between them, like Chazal say (Sotah 17b, Rashi there) about a man and his wife. It is a woman's nature to marry a man. Yonason willingly added a Hei to his name, in order to be like a wife to David. This is why David said (2:1:26) that his love was more than love of women.
Why did Yehonason love David?
Malbim: Both of them had a Ru'ach of Gevurah and Kedushah; similar matters are drawn to each other.
Why does it say that he loved him "k'Nafsho"?
