I think I want a polyamorous relationship and I don’t know how to have that conversation

I (21M) am in a very new relationship of a little less than a month right now. I have never partook in anything besides monogamy. In past relationships I have been tempted but never given in to other women. Truthfully we are still honeymoon phase a little bit and I have not been tempted by anybody else yet but I am aware that there will be temptations down the road.

I am not afraid of having conversations like this I have had many and am very proud of my emotional intelligence considering the fact that I am a young straight man and to be blunt there aren’t many of those who are mature enough to communicate as openly as I feel like I am.

The problem here is that I already know my partners stance on polyamory. She has severe anxiety and BPD and she really struggles with comparison. She has made it clear to me that even pornography is cheating to her unless it were maybe something we were watching together or sexual exploration + communication. Whenever her anxiety is really weighing on her she is very good about asking me questions and requesting some reassurance to make her feel better. And one question she asks a lot is if I am romantically or sexually attracted to anybody but her as well as will I ever want anybody else besides her. I’ve always told her no and she is the only person I want to be intimate or romantic with for the rest of my life.

It has actually been a very promising relationship so far and I am very happy with her. It has moved really fast and I can see myself spending the rest of my life with this girl. Frankly I am not interested in being polyamorous right now I only want her. But I’ve been thinking lately that it is something I may be interested in without having ever thought about it and I know that if I ever do wish to explore that, the second I bring it up it will crush my girlfriend.