Iran main to doc ager bahar shadi kari, automatic excommunicated on de spot.
But you are talking about Iranians. Marrying Iranians. But Iran has huge non Aryan (Persian) ancestry/ethnicity population now.
Upward if 40% bhai.
Which means 2 out of every 5 Iranians is a ghuspetiya over the past millennium.
Whose grand lakad daddies were in some peripheral shithole when we still lived there.
For Zoroastrians its by blood purity and paternal lineage.
Our caste lines were merged into one in India over time into the catch-all Behdin group.
But the Arhrvan (Priestly caste) remained untouched.
Now inter marriage between the two is allowed.
Till 200 years ago, even that was a complete no-no.
So my wife is from a Behdin family. I am Athrvan.
She becomes an Osti (title before your name chanted in prayers, like paidast, muktad, humbundagi, lagan, etc)by union with me. As are our kids (Osta and Osti).
In the case if a reverse, if an Athrvan girl marries a Behdin boy, she is called Behdin. She loses the priestly class. I believe in case she is widowed or divorced and happens to marry an Athrvan next, it gets complicated (translation: not actually allowed) for her to become an Osti again. Due to the prior union. Impossible if that union resulted in kids (i.e. her womb gestated a Behdin baby, and the admixture in cord blood in utero).
Now translate all of this intra Zarathushti blood purity rigidity to non Zoroastrian unions, and you get the picture bhai.