Hey new to this, but I’ve been looking into this a while me (M,20) and my girlfriend (F18) have had problems with this before but me growing as a person and being open to more things am not sure if poly is the way for me or for my relationship. She’s recently brought this up to me and I just do not know what to do I’m invested in the community I support any of my friends that do this but I’ve never seen myself as getting involved because I can’t see myself loving two people at the same time and I can’t see the only girl I’ve ever loved being emotionally/sexually attached to someone. What do I do?

EDIT: She said she would rather have me with a future then one that wasn’t guaranteed, thank all of you for helping with your advice it meant a lot!