Me and my ex are both 19, we met online and then real life, where most of the feelings developed, shortly after that, we took each other's virginity. After about ~4 months of daily texting, meeting with each other, (I go to a university, she works as a hair stylist) she simply told me, that she doesn't love me anymore. I was devastated, went and cried to her, without an ounce of reaction on her face. It's been a week now, I've tried talking to her 3 different times now with no good results. I gave up on finding anything salvageable, but I'd be glad to read some advice on here.
You cannot trust a woman only because she's spreading her legs for you. She's not your friend. That's a tough realization, but a man will never be able to 100% trust his woman in the sense of telling her everything that he thinks.
Ideally you should have a good relationship with your father and you should be able to talk about your trust issues with your father.
You should never see your girlfriend as your friend.