I have a situation , Religion issue, need advice please

I have a situation and I need advice please. Ok, my cousin, who is one of my closest friends, and I had a long conversation today. I don't know if this able to be discussed here or not. Well we were on the subject of religion. I she tells me that she here as a spiritual sister bur she isnt ttying to convience me to think "oh wow shes right i should leave him" were talking about the commandments. She came across one commandment, (which I could not find part of the commandments ) man and women should not live together before marriage. I believe everyone has different beliefs. I believe everyone deserves to be happy. I believe people should know what kind of person they are in a relationship with before they marry them. She told me that I need to tell my boyfriend/fiancé that 1 I'm finding my religion 2 I'm going to be spending more time with her 3 things will change 4 are you willing to support me while I do this Also remember no fussing no argument no discussion. I have made mistakes in the past and I am not thrilled about it but i learned my lesson. Yes, I believe in the good Lord. But I feel like I'm being pressured to say this to him. She lived with her boyfriend for 4 years and got pregnant before he proposed to her. why is she telling me this now? Should i tell him what she told me to tell him?