Is it common to call your boyfriend husband in the phillipines?

My girlfriend's father has been living with a woman in the Phillipines for 2 years now. We have our suspicions they are married and he is keeping it as a secret. The only major clue we have is she called him husband in a facebook post which she hasn't called him that my girlfriend and her sisters confronted him on it. He said it is a common cultural thing said in the phillippines but I have yet to see proof of this. He has no will made and we are doing a rent to own on his house.