Sigh.
First off your a complete piece of shit for insulting you girl-friend like that... but I'm no shit poster so I'll give you some advice.
Second...Just talk to her I understand her colon bag it may be weird or "disgusting" but its YOUR girl-friend and thus you in a sense have to accept her for who she is and just like the rest of the people here said if you don't want any of it then just end the relationship but understand how sensitive she must feel about the whole situation she can't SHIT normally and has to do it through a bag but your approach was wrong and disgusting. I know it may be hard getting used to it but if you really dont want to give up on this relationship just talk with to get a better understand of her and PLEASE for the love of GOD in heaven dont say any shit that would make her feel any worse than you already did. Example : So how did it feel when your bowl was removed. Like fuck. or worse commit suicide.
In closing.......
1.How the hell did you never notice the bag are you that incompetent or have you never hugged her before.
2.She even had enough courage to text you after she got NAKED.
3. Oh so help me dear god if you break-up with her because of the medical condition.... your the worst kind of person if you do that.... insentive bastard kind of person.
TL;DR I want a fucking girl-friend or someone to love me but you don't hear me complaining. Much less