What's the motive for telling them? Do you think it will make your relationship, or somehow change their views, for the better?
I'm asking because on one hand, I understand the need to "stay true to oneself", but on the other hand it is sometimes better to just keep things to oneself because in not doing so, you'll not improve your life in any way. Sometimes even on the contrary, you'll create problems for yourself who were "unnecessary" in the first place. I came out as an ex-Muslim (even though I today have gotten over the whole "need-to-distance-myself-from-my-negative-oppressive-experience-with-Islam", and identify as "Muslim" who simply doesn't believe "passionately" in god), and I did it because I had to get away from an abusive relationship and keep myself safe from harm. And to improve the quality of my life.
Had I been married to a normal man in a happy and healthy marriage, and was not forced to perform Islamic rituals including the hijab and niqab, I'm not sure if I would've decided to "come out" and end my "Islamic" lifestyle so radically (I mean, I like the salah and after so many years memorizing the Quran, why wouldn't I recite it from time to time?). I did it though, in order to survive.
Or in other words, since I'm a linguistic genius, why be a shit-disturber if you'll be the one with shit all over you.
That's just my opinion though