I'm a 23 year old guy and I've been struggling with this problem for quite some time (4 years): every time my girlfriend, who I trust more than anyone in this world, goes to a party without me and she gets high or drunk, I have strong anxiety attacks. Just thinking about it is making me shaking in fear, and I can't understand why. 

I like to get drunk and high too, I find it funny to spend a night messing around, I don't think it's that bad or that makes you a bad person, but when my emotions, my inner fear, kick in I completely lose my mind, and I start to think that I don't want a partner that "indulge in those kind of behaviors", as if I had this image of purity of her that gets broken by the thought of her enjoying a joint, something "bad people do".

I don't understand, it's like some cognitive dissonance. For some background, I used to be quite bullied back in high school by those who went out the night to get drunk or that smoke weed, maybe that could have led me to associate those behaviors (that have nothing to do with the moral integrity of a person) with a certain type of people.
Could it be?

Please, let me know what you think and if you have similar experiences, I'll gladly read all your suggestions and comments, thank you♥️