Hey y'all,

I have been with my fiancé for a year and recently had my best friend/ ex fiancé visit us for a month from out of state. Over the course of a month they fell in love. Before they came to visit i jokingly talked about us being a thropule especially because I knew they were both poly. That turns into now I'm having to be forced into polyamory after a year of being mono. (thinking I was going to be mono for the rest of my life) I told them that I don't think it's for me after them sleeping together twice openly, and me feeling uncomfortable each time. My partner keeps telling me I'm not giving it a fair chance and I will be so much happier when I do. What do I do?

EDIT: THANK YOU EVERYONE FOR YOUR ADVICE! I am truly shocked how many people responded!

I also wanted to add more context: For the first half of the year I had a job and took care of them, especially during the summer when they didn't work. They promised me financial stability while I am in college. Also, they want to move my ex into not only my house but my bedroom. For what would be the rest of my life. I also don't have a family and they are both the clostest thing I have.