WAS I CHEATING? MY STORY OF EMOTIONAL INFIDELITY

A week ago, my girlfriend of a year kicked me out of our apartment. She came home to find me drinking when I told her I would be working (I am a struggling writer), and, when we tried to talk about it, she just kicked me out. It’s been a week now and we haven't talked. She won’t respond to my messages. I’ve been really depressed. Before that day she found me drunk, I hadn't had a drink for almost two months. But I didn’t go sober for my girlfriend and I wasn’t able to stay off it because of my girlfriend. She’d been bothering me forever about it, and I wouldn’t do it, until I got this random call from my ex. I hadn’t seen this girl in four years, since I’d visited her at her college and found her living secretly with another guy. We talked quickly, and she asked to meet. I agreed and when I saw her it was clear she was pregnant. She told me it had been an accident, and that the guy who did it couldn't help with it at all. After this, she just asked straight out if I would go to prenatal class with her because she didn’t know anyone else in the city besides the guy who had been with her. I felt bad, and I agreed. I didn’t tell my current girlfriend about the agreement and for two months, every Tuesday and Thursday, I met with my ex for prenatal class. This was our only interaction. I’ll say again—this was our ONLY interaction. We never met anywhere else, we never had any moment of physical intimacy, and we never even talked that much to be honest. But for some reason, the classes provided some sense of happiness in my life. I stopped drinking, and my writing, as well my physical and emotional relationship with my current girlfriend, improved greatly. This went on for those eight weeks until one day I went to prenatal class to meet my ex and she was there, going through the exercise with another guy. This sent me into the drinking spell, which resulted in my girlfriend leaving. Now I am alone and unhappy and I miss my girlfriend, but I also really miss the classes. I don’t miss my ex, nothing about her personality or physicality, but I miss the calmness of the classes. I can't remember a time I've been as happy as I was in those moments in the class. I wonder then if what I was doing was wrong? Is that where my unhappiness is coming from? Was I emotionally "cheating" on my girlfriend? Should I try and get her back? Should I confess? Or should I call my ex? Is she the one I should be with? I am desperate and need your caring advice. Thank you.