Why was David so pained over Yehonason's death?
Malbim: (a) Due to his virtue - Na'amta Li Me'od. (b) Due to his great love for Yehonason.
Why does it say "Nifla'asah Ahavascha"?
Radak: There are two signs of being feminine, to show how strong [the love was]. I explained this regarding "Hechbasah" (Yehoshua 6:17).
What is the meaning of "me'Ahavas Nashim"?
Radak citing Targum Yonasan: More than love of two women (David's wives 1 ).
Radak citing his father: More than women love their husbands and children. This is a very strong love!
Malbim: Love of women is due to what is pleasant or beneficial. David had intrinsic love [of Yehonason 2 himself].
Alshich: Even though women love their children, amidst pain of birth, they swear not to be intimate with their husbands again. You, even when your father threw a spear at you due to your love for me, you risked your life to tell me to flee!
Chomas Anach: Refer to Shmuel I, 1:18:1:1)
Alshich (Bereishis 32 DH v'Ytzav): David's wife Michal saved him in this world, and Avigayil saved him from a sin that would have withheld him from good in the world to come.