Why do you think that? Being bi doesn't render you incapably of being in a monogamous relationship, it doesn't mean that you can't be fulfilled by a partner of a particular gender. It just means that you can be attracted to men or women. She's with you now and choosing to be with you.

Again, I don't think she won't be monogamous but that it will change up the boundaries that will have to be set up in our relationship. Things like her sleeping in the same bed as friends, or touching friends in inappropriate ways, I'm no longer going to be comfortable with those things.

Experimenting and exploring identity is perfectly normal for young adults and claiming a bisexual identity while you're in a monogamous heterosexual relationship seems pretty far down on the table of risky behaviors.

I definitely did a bad job explaining in my main post, I didn't mean it to come off like me thinking her being bi is unstable, but rather the idea of her just saying this like she's just said all the other extreme and dramatic things.

Thank you for the advice though, I apologize for being unclear