I'm very adventurous in bed and have always been an advocate of trying new things, although this is totally not my thing. If she's my girl, the thought of her with someone else does not sit right with me and I don't know how to proceed. I like her a lot and would not be able to feel about her the same having witnessed another dude have sex with her - that does NOT turn me on a bit.

At the same time, I really like her and want to be supportive of whatever she wants to explore. She says maybe I'll hate it and never want it again but she wants to try it.

I've been reading about what to do when your partner wants to have a threesome and I've found no luck in clearing my ambiguity on what I should do. What are my options and how should I proceed?

Edit: I am being torn apart on the thought that this might be an opportunity to grow closer to her and leading to us being even more comfortable? She mentioned she asked all her exes to try it and all of them were highly against it..

Edit 2: She suggested we become exclusive FWB and don't get in a relationship so that it may not stand in the way? WTF?