I don't how to do this
I've come here seeking help and advice. I'm a 23 yr old woman. I've been in a mono relationship with my fiance for 4 years. 4 months ago we met a young woman while traveling to a concert who was looking for a ride. We all hit it off and I thought she'd be a great friend. Then a few weeks later my fiance tells me he's attracted to her and want to have a threesome with her. I was hesitant. I like her but I'm not attracted to her.
Then just recently he tells me he wants to have a relationship with her and have her be a girlfriend. He wants her to be "our" gf. This has completely come out from left field for me. He's always touted monogamy as being the utmost important thing in a relationship and now he's changed on me.
I'm confused, hurt and feel like I'm coming apart. I can't stop crying and I feel lower than dirt. I love him, I've given him everything. He saved me from a terrible relationship and has helped me deal with past abuses I dealt with. I was fully prepared for a mono relationship with him and now I feel like I'm about to lose everything I've known and held dear.
I don't know if I can give him what he wants. I don't want to lose more time with him. He spends hours with this girl working on music and chatting online and I feel like I'm competing for him. For his attention. I just don't to do. I don't who to talk to. I feel I can't talk to our family or friends and I feel isolated and alone.
Please somebody help me. I need help to save my relationship.