I understand some of how you feel.
I support interfaith relationships and marriages.
Religion is only an issue when people make it an issue, usually in an attempt to impose it or use it as their weapon.
I'm lazy catholic and my best friend is a follower of the shia islamic sect led by the aga khan.
We have both dated guys of a variety of religious beliefs and backgrounds.
I have a militant atheist father, conservative catholic mother and religious fanatic maternal grandmother.
My mother was raised in a brutal ultra-traditionalist catholic household that rejected vatican ii reforms, viewed medieval religion as perfect and the modern world as evil.
She married her soulmate and they have been together for more than 4 decades.
But her freedom came at a heavy price.
My mother was disinherited and almost beaten to death when she came home from uni to tell her family that she had decided to marry an atheist.
She never spoke to her father again and was banned from attending his funeral on his orders.
Put your health and safety first.
Always trust your gut instinct and listen to what your common sense is telling you.
Don't put yourself in a position where you are a teenager at risk of homelessness or violent physical attack.
Nor an adult dependent upon hostile relatives to provide your with access to food and all the basics.
Your parents reactions and ultimatums show you some of the very worst elements present within your household.
Regardless of whether you continue with the relationship, you have a choice to make.
You need to ask yourself whether as an adult you want to continue remaining in contact with relatives that behave in this way.
Whether you are willing to allow the childhoods of any future children that you have to include seeing or hearing your parents noisy hostile attitudes, ultimatums, insults and threats.
Good luck!