In my opinion it always seemed like Firestar loved Spottedleaf more after she died than when she was alive; the way I saw it it was as if Spottedleaf never lived long enough for the relationship to seem real.

Agreed

I never really thought of them like they were in love. He was a kit(maybe not born) when she became medicine cat. I always thought they had a student/mentor or mother/son relationship.