My Jewish ex-wife converted to Methodism when she married her new husband. Melanie, my youngest now goes to a Methodist church. This doesn't bother me much. But what does bother me is that Melanie now repudiates her Jewish heritage. The other day at lunch I talked about her ancestors. I said that through my side she's mostly German, English and Irish, and through her mother's side she's mostly Polish and Jewish, to which she exclaimed, "I'm not Jewish. Stop saying that."
I think she's confused about the difference between racial heritage and simple religious belief. I can proudly say I'm mostly of Irish descent without calling myself Catholic, and it's the same principle for her and her Jewishness, but she wasn't having it.
I wrote to my ex to express my dismay at this and she wrote back, "Don't discuss religion with Mel. You stress her out. It's really not your concern."