My mum calls my dad "PA", and my dad calls my mum "MA"...
I THINK, we Filipinos just love the idea of using ENDEARMENTS to our partners. Gf and Bf thing in the Philippines has got different endearments such as (Bhe, Boo, Baba which are all short names for Baby; Mhe, Moo, Dhe, Dada which are all short names for mommy and daddy... Even others call their partners strawberries, pears, etc). We find these endearments romantic... We uses these endearments regardless of the age of our partners.
Here in the UK I have found people use endearments (DARLING, LOVE, MY LOVE, HONEY, SWEETHEART, DEAR) such an ordinary thing to call anyone. In the Philippines, using those terms to someone is really awkward. We only use those to someone very special to us like gf/bf/husband/wife.
Have you all notice that we never call our mother, brother, uncle, auntie, brothers, sisters just on their names? We always attach KUYA or ATE to our brothers and sisters names and even to anyone who are older than us...this is how we show respect to them. We never call them by their names alone...