Hey, I understand you.
My father left our family's Catholic faith when I was 3 and became a hardline Calvinist-variety Baptist. My parents divorced several years later, and since he had us on weekends, he took us to Baptist churches on Sunday. I only went to mass on holidays and when one of my many cousins had a First Communion or Confirmation.
He became very anti-Catholic and threatened my mother into not allowing us our own First Communions and Confirmations. My sister, the youngest, was not even baptized (still not, sadly).
Growing up, I heard so much stuff about the Catholic Church's "idolatry," "pagan ritual," "baptizing babies," "Mary worship," etc. His favorite Christian minister and theologian is John MacArthur, who insists that anyone who believes in the "false Catholic gospel of salvation by works" is damned.
I always found this strange because there are many devout Catholics in his side of our big family---some have had 8, 10, 11 kids and go to Society of St. Pius X masses (my mother's side is not very devout).
So my father did all he could to bring me up Baptist. Well, it didn't take. I grew up a student of history (I'm now doing it professionally), and through such studies and via my spiritual development, God led me to the Church of my birth a couple years ago (several years before that, I had narrowed my choice down to Catholicism, Orthodoxy, Anglicanism, and Lutheranism---I almost became an Anglican and then very nearly became Orthodox). I received my Confirmation last year, unbeknownst to my father.
I still have not told him. I am avoiding it at this time, though if he asks me straight out, I will be honest. We have had discussions about various topics, and through them he knows that I believe in the Real Presence in the Eucharist, baptismal regeneration, infant baptism, free will, and other things common to most liturgical churches. This knowledge causes him to explode in anger at me when I defend these doctrines, and afterwards he will not speak to me for a long time. When I visit, I go with him to his Baptist church (and discreetly slip off to mass on my own)---he doesn't like it at all when I pass on the "Communion" of grape juice and crackers offered to me. I think he suspects (and fears).
I think he might see my Catholicism as more of a kind of apostasy than that of my family's because he tried to bring me up as a Baptist. I guess I "fell away" (into the outstretched arms and bosom of the Church of Our Lord
At some point he will be ready. He has softened a bit lately---now he no longer says that Catholics (and Orthodox) are all going to hell, and he now admits that John Paul II was a good guy, even if he did worship Mary.