TELLING MY PARENTS IM MOVING OUT

So I need a little help! I am 18 and I have been planning to live with my boyfriend since we met, but there is a problem I want to move in with him by this Wednesday, but I haven’t talked to my parents about it, yes I know I don’t have to but I also don’t want to leave on bad terms with them as I know they aren’t going to approve because they are both very religious and against anything that may lead to sex (obviously I’d be sleeping with him.) it’s so bad that when he used to come over they made us sleep in separate rooms, I feel bad for leaving because they just paid for my car and to fix it): I don’t want them to hate me but I do want to start my life with my boyfriend. As he and I are both very ready to do so. I just don’t know how to go about bringing it up or even saying it, has anyone had this similar problem ?