3 years since I came out, parents still don't accept partner

28/F, I'm in a long-term LGBT relationship and I came out to my parents 3 years ago. They didn't take it well.

My dad did not approve when I came out, and my mom (who was initially okay with it) also turned her back on me. They were initially threatening to kick me out of the house, pero nakita nila na self-sufficient naman na ko and the threats aren't working anymore. I also moved out a few years back. So they've taken to pretending my partner doesn't exist and questioning me when we do things together kapag bumibisita ako sa bahay or tumatawag sa kanila.

I've tried countless times to explain my relationship but they are not hearing it. Umabot na ko sa pagsusulat ng super haba na letter just to get them to accept us pero wala pa rin. They keep reasoning na hindi daw sila homophobic, ayaw lang nila sa family ng partner ko and they don't think I should associate myself with her. My mom also likes asking me annoying rhetorical questions na bakit daw lagi kong kasama yung partner ko? Na honestly napapagod na kong sagutin so sinasabi ko na lang na partner ko yun, if di pa rin nila tanggap then maybe sila na ang problem. When I do things for myself, sinasabihan akong bastos and walang consideration for their feelings.

How do you deal with parents who act like this??