People forget that sakura actually has a strong relationship with Sasuke.
Because it's unreasonable that people forget that... "truth".
Honestly, anything goes when it comes to Sasuke because he's so "mysterious" and keeps his feelings (that don't involve murder or mass genocide) close to his heart. Kishi could have written it either way and I wouldn't have batted an eyelash at it.
I think it's pretty fair game for Sasuke to develop feelings for either girl - Sakura because she's innocent, naive and dedicated to him. Karin because she is jaded, suffered and dedicated to him.
Sakura has earned her status as "strong" by excelling as a med-nin, as Tsunade's apprentice.
Karin by genetics as an Uzumaki, possessing sensory skills "unlike any other" according to Sasuke, chakra chains etc.
If (and that is a big, massive, huge "if") Salad was Karin's kid then I don't think Sasuke wouldn't have
no feelings for the mother of his child.
But love... I would have thought his capacity to love (beyond Naruto) at this point would be seriously flawed. He's a broken man. I kind of hoped Kishi would have kept him as the Last Uchiha indefinitely. I find it difficult to swallow the belief that he "loves" Sakura... I think the only person he'd open himself up to truly love would be his own child.
... that's just my opinion. Half-assed as it is.