<human>: Could you distill the essence of the text into 1-3 sentences?

I broke up with my then gf because I felt like we had grown apart. We started dating when we were 17 y/o. We were both going through some turmoil in our lives. I was glad to be there for her, and have her there for me during these times. She is the woman I lost my virginity to, and the only one I have had sexual relations with. But we went to college, the same one, and it became apparent that we were heading in different directions. 

I gathered the courage to end the relationship. It wasn't easy for either party. In the following weeks I was confident I had made the right decision, and I still am. But now, around 2 months later, I'm having a tough time moving on. 

The thought of her being with another man makes me nauseous. I've seen her around campus a few times, that same thought crosses my mind, and I get the same nauseous feeling in my stomach. We were both straight edge when we were together. I know she has gone to parties and got drunk. I too went to a party, but didn't drink. Knowing that she could go to a party, get drunk, and have a one night stand makes me sick. I very well know that I could go out and do the same, and that makes me hypocritical, but this feeling almost feels out of control. Is this a feeling of jealousy? I can't put my finger on the reason I feel sick when I think about, or see her. 

At the same time, I know her and I are already different people then when we were dating. I'm having more fun with my guy friends than I would have had I stayed in the relationship. It makes me positive that I made the right decision. 

I just need some advice to help me move on. I'm tired of having mixed emotions.
<bot>: Broke up with my then gf, and now I feel sick when I see her, but don't know why. I know I made the right decision. Help me clear my mind.